MS. KATHERINE LANPHERThanks for joining us. I'm Katherine Lanpher sitting in for Diane Rehm. Belgian authorities have named two of the suspects killed in a deadly terror attack yesterday at an airport and subway station. They're still searching for a third suspect. Meanwhile, three western states here in the U.S. held primaries and caucuses yesterday. Frontrunner Donald Trump and Hillary Clinton won in Arizona, but Trump lost to Ted Cruz in Utah, complicating the path to nomination and Vermont Senator Bernie Sanders came away with victories in two states.

MS. KATHERINE LANPHERJoining me in the studio to discuss election results, the latest on the Belgium terror attack and what the candidates are saying about those attacks, we have Ron Elving, senior Washington editor for NPR News. You can also hear him on the NPR politics podcast. Mark Mazzetti, national security correspondent for the "New York Times," author of "The Way Of The Knife: The CIA, A Secret Army And A War At The Ends Of The Earth."

MS. KATHERINE LANPHERNora Bensahel, a distinguished scholar in residence at the American University School of International Service and Demetri Sevastopulo, Washington bureau chief for The Financial Times. I want to remind you, of course, that you're part of this conversation, too, and you can join us at 1-800-433-8850 or join us at drshow@wamu.org and, of course, our website is www.drshow.O-R-G.

MS. KATHERINE LANPHERMark Mazzetti, I'd like to start with you. Let's just get caught up on the latest as the information keeps shifting, the latest on this investigation in Brussels.

MR. MARK MAZZETTIWell, today, authorities in Brussels announced the identities of some of the bombers of yesterday's bombers and two of them were brothers who were known to Belgian authorities. Both of them are believed to have died in suicide attacks yesterday. One of the brothers killed himself at the airport. One of the brothers killed himself in the subway attack. These were -- this is part of what is believed to be either a cell or a wider network in Belgium that was not only responsible for yesterday's attacks, but also many of them believed responsible for the Paris attacks last November.

MR. MARK MAZZETTISo I think it's really best to think of this as sort of one long on-going story over the last four months. You had the Paris attacks in November. There were authorities all throughout Europe looking for some of the individuals still at large. One of them was picked up last Friday as one of these raids in Brussels. And then, you see yesterday's attacks and many of them, authorities are just learning really are all part of one larger network.

LANPHERAnd how do we know how police were able to identify those suspects?

MAZZETTIWell, they have video footage of some of the suspects from yesterday, at least at the airport. There was close caption television showing at least one of the brothers and two other men. One of those men is still believed to be at large. You also have...

LANPHERHe's the man in the white coat...

MAZZETTICorrect. And he's now...

LANPHER...as we've heard him referenced.

MAZZETTI...perhaps the most wanted man in Europe. And then, you have the interrogations going on of other captured suspects, notably the senior suspect captured last Friday who is believe to be talking to authorities and that's sort of one of the interesting aspects of this is how much did the arrest last Friday maybe trigger what we saw yesterday. Now, these plots were no doubt in the works before the arrest last Friday, but it is very possible, and a lot of terrorism experts think, that maybe these plots were accelerated because they know that this man may have been talking and they may been thwarted if they didn't move soon.

LANPHERAnd Nora, this man, Salah Abdeslam, ISIS has claimed responsibility for the attack, but given that there was this arrest, how did Belgian authorities fail to see this coming or is that a misrepresentation of what actually happened?

MS. NORA BENSAHELWell, these men were known to Belgian authorities, as Mark said, but they were not on terrorism lists. They had been picked up for regular criminal activity at a fairly low level, from what I understand. And so there's -- but there's a really good question about the effectiveness of the Belgian security forces, both the police and the intelligence services, about, you know, where they're getting their information and how they're sharing information.

LANPHERI have a question, which is are they one unit or is it sort of like here when in the wake of 9/11, we discovered that our emergency responder system needed reorganization?

BENSAHELNo, they're different units. They are in most countries. So there's a question about their cooperation within Belgium, but more importantly, there are questions about how those services cooperate with their counterparts elsewhere in Europe. A lot of terrorism analysts, particularly in Europe, have criticized the European-wide level of sharing in terms of both terrorism expertise and knowledge and the intelligence services, sharing information on people.

LANPHERAgain, it sounds like something we went through here in this country where we had to learn how to share.

BENSAHELYes, except it's complicated by the fact that you're talking about sovereign governments now. At least in the U.S., you know, the president is, theoretically, in charge of all of them, although there are bureaucratic issues that have to be handled. Here, you're talking about cooperation among many different national jurisdiction and some involvement of the European Union as an institution as well.

LANPHERCan we talk for a moment, Nora, about why Belgium, why is there supposedly a hotbed of terrorists there? Even that sounds like we're assuming too much. But let's talk for a minute about why Belgium.

BENSAHELWell, it's really Belgium and France and both countries have had a problem integrating Muslims into society. Other European countries have had that problem as well. But for some reason that I'm not sure it's completely understood, many radicalized Muslims in France and Belgium have traveled to Syria and traveled to Iraq and other places and have learned and picked up a lot of terrorist tactics, have built their network and so on and then returned home to conduct these types of attacks.

BENSAHELThe two brothers who Mark mentioned before, it was announced this morning, were Belgium nationals. They were born in Brussels so this isn't, you know, someone from Syria, a refugee or someone coming into Belgium or, you know, that wasn't the case in France in November. These are home grown people who become radicalized who are traveling abroad, learning more about the tools of the trade, if you will, and then coming home and conducting these attacks.

LANPHERIt's interesting because I've definitely heard theories that, in France, because of, you know, the law of republic, because they do not want -- the want assimilation totally, and also there's a blocked path for anyone who's not considered truly French. And often, when you have Muslim immigrants, no matter what, unlike the U.S., you're still a second generation newcomer instead of a French person.

LANPHERBut in Belgium, is that also the case? I had the impression that Belgium was more welcoming.

BENSAHELBelgium is a more assimilated society, particularly because it has two dominant ethnic groups, the Flems and the Walloons, who are involved in a very complicated power-sharing arrangement. Belgium politics is notoriously unstable because of that. But it is a general trend throughout Europe, there are other countries where this is true as well. Germany, Muslims are not as well integrated into society because of some of the culture there.

BENSAHELSo, you know, yes, Belgium, I think, is known as a more welcoming country where it's easier to assimilate, but these problems still remain, nonetheless.

LANPHERDemetri, how are European governments reacting to these attacks?

MR. DEMETRI SEVASTOPULOWell, excuse me, as Nora said, one of the difficulties is that while it's difficult to get cooperation in the U.S. when you've got different states involved, in Europe, you have multiple governments. You have different cultures. You have different languages and so it is very difficult to coordinate. You also -- I think American intelligence officials would say that the Europeans and particularly the Belgians don't have the resources or the skills needed to cope with this threat given the level of the threat that exists right now.

MR. DEMETRI SEVASTOPULOI mean, Mark would be able to speak to this more than I would, but the number of people you need to -- in the intelligence community, just to monitor one suspect is, you know, several dozen. So if you have hundreds, possibly several hundred people that you're monitoring in the country, that's a huge manpower that you need to be able to do that and it's not clear that the Belgians really have that at the moment.

LANPHERFrench President Francois Hollande said yesterday that Europe is at war. So what does that mean for the future of how Europe looks?

SEVASTOPULOWell, Europe, I mean, you have to look at what's happening in Europe over the last couple of years. I mean, there's a lot of talk in America about Syrian refugees coming in and, you know, whether that's a Trojan horse for terrorism, et cetera. In Europe, you have had huge numbers of migrants coming from Syria. You have these communities in Belgium and in Paris in France where the assimilation is not as great as it could be.

SEVASTOPULOAnd so the recipe is there for these kind of things to happen and it's happening in such a rapid scale that I think, frankly, everyone is really struggling to get their heads around the problem and work out how you deal with it. And at the end of the day, I think there's also recognition, as there was, in Ireland when I was growing up with terrorism with the IRA that you can talk about stamping out terrorism all you want, but the reality is, it's impossible to completely eradicate it.

LANPHERAnd so the idea of a free and open Europe, is that the question these days?

SEVASTOPULOWell, I mean, if you look at the case of the two brothers who were picked up in -- who conducted the attacks in Belgium, if they are Belgium nationals, they can travel across European borders under the -- you know, there's nothing to stop them. We have the Schengen visa arrangement in Europe which allows people to, once they're in one country in Europe, to travel visa free, passport free through many other countries in the region.

SEVASTOPULOSo that is coming under threat. I mean, there is a lot of pressure to try and tighten up these systems and make some of the poorest part of the borders tighter.

LANPHERYou're listening to "The Diane Rehm Show." I'm Katherine Lanpher sitting in. If you'd like to join us for our conversation not only about the latest on the terror attack, but also about yesterday's primaries and caucuses, you can call 1-800-433-8850 or send an email to drshow@wamu.O-R-G. Find us on Facebook or send us a tweet.

LANPHERWelcome back. I'm Katherine Lanpher, sitting in for Diane Rehm. And we are continuing our conversation, looking back at both the continuing investigation into the terror attack in Brussels and its possible links to how people behaved yesterday at the polls, in what's called the Western primaries, Western Tuesday. We're going to turn to Ron Elving, senior Washington editor for NPR News and get his take on what exactly happened yesterday.

LANPHERThe main thing I want to know first is we've been talking about these terror attacks. There was a lot of commentary last night about long lines and how -- some supposition that perhaps it was linked to the terror attacks.

MR. RON ELVINGThat's an attractive narrative. In fact, it appears to have been as much linked to the lack of sufficient precincts. They had literally reduced the number of available precincts in Phoenix, in Arizona, obviously the biggest city in the biggest state that was voting yesterday, and for budgetary reasons and perhaps for some other more nefarious reasons, the state of Arizona has seen fit to decrease the number of places where people can vote.

LANPHERSo that's what decrease in precincts means? Okay.

ELVINGThat's right, and so there were just fewer places to go vote, and people, as a result, had to stand longer in line. Now that's part of it. Obviously the sudden enthusiasm of many voters this entire season has been in some degree linked to international events, especially on the Republican side. On the Democratic side, perhaps it's linked as much to enthusiasm for Bernie Sanders and his insurgent campaign.

LANPHERAnd also talk for a minute about this stance in -- like for instance in Arizona, which we just mentioned, Trump's stance on immigration.

ELVINGYes, that's the key for him, and of course if it doesn't work in Arizona, it's hard to imagine where it would work. There is a great deal of anxiety among Republican voters in Arizona about the changes that the state has been going through because of immigration there, but immigration's a very old story in Arizona. And you also have generations of Republicans, such as Barry Goldwater and John McCain, who have had a much more, shall we say, cosmopolitan attitude towards the changes in Arizona and have long embraced them so as not want to wish or to characterize the attitudes of all Arizona Republicans, by any means, as monochromatic.

ELVINGBut right now the big symbols of the party are former Governor Jan Brewer and Sheriff Joe Arpaio of Maricopa County, that's Phoenix, and they of course have a very, very strong line with regard to immigration and with regard particularly to people in the country illegally. So that was a dominant issue here, as it has been in so many other Republican primaries, and anything that increases anxiety in general about people from anywhere other than here tends to help that particular issue be salient and drive the results.

LANPHERLet's turn to Bernie Sanders for a minute, big wins in Idaho and Utah. Can I just say as, you know, a civilian in politics, Idaho and Utah and Democrats, and you never put those all together in the same sentence before.

ELVINGWell, Arizona's not a great state for Democrats, generally speaking, either, and that's part of what you get into when you get to the West. When you get into the mountain time zone, it's pretty much Republican territory, but, but what happens in these places, and Barack Obama demonstrated just how much power these caucuses can have, there is the potential for the well-organized campaign to flood the caucus, which is something that requires people to make sort of a commitment and come out.

ELVINGYou can flood the caucus with the enthusiastic supporters of the more, if you will, driven campaign, such as Barack Obama's in '08, certainly Bernie Sanders in 2016, and you can dominate the vote the way he did in Idaho and Utah last night so that he picks up 75, 80 percent of the participants. That gives him a disproportionate share, two-thirds or three-fourths, of all the delegates from those states, and as a result, he was able in those two states to get almost as many delegates, or approximately the same number of delegates, it looks like about a split on the night, even though Hillary was winning big in the biggest state that voted.

ELVINGIn Arizona she really was quite dominant, almost 60 percent, so that is great news for her. It would've been terrible if she had not done so well in Arizona for her. It would've been bad if she was not able to carry her lead among Hispanics and others in Arizona. But Bernie was able to even the score for the night by doing so well in those two.

LANPHERAnd I know there are people keeping score at home when it comes to delegates. So with Republicans, what are we looking at?

ELVINGWell, Donald Trump is at 739 delegates at this point and Ted Cruz at 465 so still a very substantial lead for Donald Trump. However...

LANPHERAnd we need 1,237 to win the nominate...

ELVINGThat is the magic number. Donald Trump has started referring to it as an arbitrary number. It's only arbitrary in the sense that it's half plus one of the delegates.

LANPHERIt's huge, this number.

ELVINGWell, it's not some magic number, it's simply the delegate math is that if you have more than half the delegates, you win the nomination on the first ballot. So he has a substantial lead there, but his victory in Arizona last night was also somewhat overshadowed, or somewhat shadowed, by what happened in Utah because there Ted Cruz was able to get over 50 percent of the vote and therefore claim all 40 delegates. That was almost as good as Donald Trump getting all 58 in Arizona.

LANPHERDemetri, I wanted to turn to you because I know you're covering the campaign for the Financial Times. Talk for a minute about Cruz' big victory in Utah and what it means.

SEVASTOPULOWell, I think it's huge. I mean, as Ron said, first of all, it gave him all of the delegates where had he got less than 50 percent of the vote, the delegates would've been split between the candidates. If we're heading towards a scenario where Donald Trump may get the 1237 delegates at the convention in July, or he may be a few shy, if he's a few shy, then the delegates that Ted Cruz picked up last night are really, really important.

SEVASTOPULOAlso the scale of his victory, I mean, he got 69 percent of the vote that's been counted so far, and I think this is the first that Trump has come in in third place.

LANPHERIs it a surprise, though, that that happened in Utah?

SEVASTOPULOWell, it's not a surprise in the sense that it's a very Mormon state. It was said that Mormons were not favorable to Trump because of his, you know, his comments on minorities...

LANPHERPut this delicately, okay.

SEVASTOPULOYou know, on religions, on other things. However, Trump has done pretty well with the Evangelical vote across the country in ways that people hadn't expected and sucked or siphoned support away from Ted Cruz. In Utah he didn't do that. Another difference last night was in Arizona, there was an awful lot of early voting that happened before Marco Rubio and some of the others got out of the race. Where would those votes have gone had all the votes happened yesterday? In Utah, we didn't have that.

SEVASTOPULOAnd so Utah may be a better reflection of what's happened in the last week in the Republican race than Arizona.

LANPHERNora, there were four Mormons injured in the Belgium attacks yesterday, and I'm wondering how much of a role, if any, do you think that might have played.

BENSAHELIn the Utah results? Again, I'm not sure that it has a huge impact there because, you know, these issues have been underway for a long time. It may underscore the urgency of people getting out to vote, feeling like their vote matters in some way. But, you know, by and large Americans don't vote based on foreign policy, even when there are big international incidents. They tend not to affect elections too terribly much.

BENSAHELThey may affect the rhetoric, they certainly affect the campaigning because candidates can see a wedge against incumbent officials, in this case not just President Obama but Hillary Clinton's seen as his natural successor in the Democratic Party, but, you know, when -- that tends not to drive who and -- who people vote for and whether they turn out.

LANPHERDemetri, I want to go back to you for a moment and talk about Florida Governor Jeb Bush reportedly has endorsed Ted Cruz this morning.

SEVASTOPULOWell, this is amazing. I think what's happening is you've got Ted Cruz, who for a year has been running against the Washington cartel, against the Republican establishment, and over the last couple of weeks, he's picked up the support of Mitt Romney, the great statesman of the party. He's now got Jeb Bush, probably because Bush hates Trump more than anyone else on the planet, given that he was pilloried for months as low-energy Jeb.

SEVASTOPULOBut you also had Lindsey Graham, the South Carolina senator, who last month said if you killed Ted Cruz on the floor of the Senate, and the trial was held in the Senate, no one would convict you. Lindsey Graham has come out and endorsed Ted Cruz. So basically the party, or the establishment, is deciding that we would rather go with the lesser of two evils, and they see Cruz at this point as the lesser of two evils, because he's more consistent, whereas with Trump they feel they don't know what they're going to get.

SEVASTOPULOAnd someone said to me, a senior Republican, we would rather lose big with Cruz than lose ugly with Trump.

LANPHERMark Mazzetti, I'm going to go to you. Speaking of Donald Trump, he said yesterday that he favors water boarding terror suspects, and he suggested that both here in the United States and in Europe we're at a disadvantage for not taking advantage, if you will, of that technique.

MAZZETTIYeah, and this is not the first time he has advocate what he says, you know, water boarding or tougher measures. And it just goes to my colleagues on the panel here, this issue of how, you know, sometimes, you know, demagoguery can be good politics on these issues, where you're saying the most outrageous things to play to people's fears and get them scared enough to think that only a tough national security policy, the toughest national security policy, will keep you safe.

MAZZETTISo not only is it water boarding, but you heard two days ago Donald Trump, when talking to the Washington Post editorial board, not really rule out the idea of using nuclear weapons against ISIS. There's just so many different things that we could be discussing on this front. Ted Cruz yesterday talking about basically putting Muslim communities in America on lockdown.

LANPHERNow what is -- you know, when I watched his actual speech on that, I wondered if what he was trying to say was a little less hyperbolic than that. Ron Elving, you look ready to respond.

ELVINGHe said we should be patrolling and securing Muslim neighborhoods and communities before they become radicalized. Now a lot of people's reaction to that was, quite immediately, what better way to radicalize them than by patrolling and securing them.

LANPHERBut, you know, I think the words patrolling and securing because then he also referenced a program in New York that was very controversial.

ELVINGYes, and there is a notion here that there are somewhat ambiguous terms involved in patrolling and securing. Everyone wants their communities to be, in some sense or another, patrolled and secure. But is that what he meant? Or did he mean that they should be in some sense or another suppressed, they should be in some sense or another occupied so as to not produce the kind of terrorism that we've seen in Paris and Brussels?

LANPHERNora, you had wanted to say something.

BENSAHELYeah, I think it's important to note that the statements that we've been talking about from both Donald Trump and Ted Cruz really would have no relation to the causes of the terror attacks yesterday. I mean, the dynamics in Europe are very different. There is a homegrown support network that enabled a lot of these suspects in the aftermath of the Paris attacks to remain hidden. You don't have that in the United States because Muslims are far more assimilated in the United States.

BENSAHELMost Muslim communities are -- cooperate with the police and intelligence forces, and, you know, that kind of dynamic most likely wouldn't happen in the U.S. The discussion of water boarding and, you know, torture as a possibly effective tactics again has nothing to do with what might have led us to know about the terror plots in Brussels yesterday. So the candidates all do need to respond to such a dramatic world event, but those two in particular didn't really get at the causes of the terror attacks. The other candidates, both Kasich and Clinton, and Sanders as well, talked about more standard, cooperating with the international community, trying to get at the root of this.

LANPHERI'm Katherine Lanpher. You're listening to the Diane Rehm Show. Remember, we'd like to have you respond to us, as well. You can join us at 1-800-433-8850. Or send an email to drshow@wamu.org. Or you can find us on Facebook or send us a tweet. I'd like to go ahead and take one of our calls and emails here. Matt, I'm going to start with you on this one. This is from Annie, an email. I have -- I have a question. How do authorities know that the three men pictured in airport security photos are the terrorists?

MAZZETTIThat's a good question. They are able to take the video, they are able to do -- to put it up against images that they may have on files of people who have prior records. They are also able to scan other images that were taken in closed-circuit television and basically try to do matches through facial recognition. And then they can also basically survey the scene after the crime and after the attack and basically also, if they can find bodies, they can find out who may have been the -- who may be dead and who may have been suicide bombers.

BENSAHELThey were also able to identify the taxi driver who picked up the brothers and a colleague on the way to the airport, the three men in that photo. And the cab driver actually took them back to where he had picked up those suspects.

LANPHERAnd what -- what made him -- what made the cab driver suspicious, Nora?

BENSAHELI'm not sure that's been released yet, but...

LANPHERDemetri?

SEVASTOPULOApparently the suspects, they wouldn't let him touch their bags when they were getting out of the cab. And there's also a story, which is unconfirmed as of yet, but that they had asked for a bigger taxicab to come to their house, but there was a misunderstanding. So they weren't actually able to bring all of the equipment or the bombs that they wanted to bring because of that.

LANPHERLet's go to Steve. He's calling us from Conestoga, Pennsylvania. Steve, welcome to the Diane Rehm Show.

STEVEHey, thanks a lot. I'd like to comment about how it's becoming pretty obvious how the Republican leadership is becoming opposed to the voters, the Republican voters. Like all these Republican leaders are coming out and endorsing, you know, almost sworn enemies, especially in the case of Lindsey Graham, and the voters just keep consistently voting for Donald Trump.

LANPHEROkay, Steve, thanks.

ELVINGYes, the voters have been voting for Donald Trump in a plurality of the Republican Party. It generally speaking has not been anywhere near 50 percent of the Republican vote. Of course as Donald Trump points out, it's a huge field until just very recently, and so the votes were being fractured among many candidates. But it is not necessarily the will of all Republican voters that Donald Trump be their standard bearer or be president.

LANPHEROkay, thanks, Ron. Demetri?

SEVASTOPULOI agree that the endorsements from the establishment probably have very little impact on the voters who are going to vote for Trump and/or Cruz. But they will become important when we get closer to the convention because as you try to work out who are the Republican Party members who are the delegates, who attend the convention, who will actually do the voting, having a network on the ground is extremely helpful, and it tends to favor people with party establishment ties.

LANPHERWe're going to go to another caller. This is Gabriel on Staten Island, New York. Hey.

GABRIELHi, how's it going? I just wanted if you guys could comment on why the attacks in Brussels are getting so much attention in the media when the attacks in Turkey that just recently happened pretty much hasn't -- hasn't really been talked about.

LANPHERMark, I'd like to have you take that.

MAZZETTIIt's a good question. It comes up often. The -- I think there -- it's a fact that these large scale attacks in Western European capitals, in places like Paris and Brussels, will attract the media's attention. There's a newness to it, as opposed to there have been attacks in Turkey and have been, you know, for several years because of terrorism. So the media may be covering something that appears newer. I'm not saying it's right. It is the way the media responds to certain things.

MAZZETTIThe same thing happened several months ago. I think in Paris, at the same day or days before, there was a major attack in Beirut, and in fact with larger losses of -- loss of life than there was in Paris, and the -- it gets less attention.

LANPHERYou know, I'm going to very briefly just say that I believe it does get covered, but people don't necessarily read it. I know the New York Times covered it. I know National Public Radio covered it.

MAZZETTIAnd I think people react, and sometimes react to cable television, the wall-to-wall coverage, than for instance just yesterday the Paris attacks, the Brussels attacks, got on all the networks that, you know, it hasn't had before.

LANPHERAll right, we're going to come back to this conversation. We're going to come back to your calls. You're listening to the Diane Rehm Show.

LANPHERI'm Katherine Lanpher, sitting in for Diane Rehm. We are talking about the results in primaries and caucuses yesterday in three states in the West. We're also talking about the ongoing investigation into the terror attacks in Brussels and what possible connection, if any, the two might have as the American people react to those attacks. I want to get back to politics for just one minute, and I'll turn to you first, Ron. And that is how the Democratic candidates, Bernie and Hillary, responded, if at all, to those attacks yesterday.

ELVINGBernie Sanders, of course, and Hillary Clinton were immediate in their responses. Bernie Sanders said ISIS must be destroyed and Hillary Clinton said that she used that word steady, which is becoming her watch word, I think, with respect to many things, but especially national security policy. She said we needed a slow, steady, smart and strong response. Four Ss. And we may hear that again. She's giving a speech on national security today at Stanford University and we expect to hear much the same theme.

ELVINGBut both Sanders and Clinton also emphasized something else and that was that this should not be used, this incident or any terrorist incident, should not be used as a pretext for setting people against each other. For setting people upon each other in the sense of religious groups, international, national, ethnic groups. And this should not be used in the way that they both warned it would be used by candidates on the other side.

LANPHERDemetri.

SEVASTOPULOI mean, as Nora mentioned earlier, a lot of the candidates took aim at what Trump had been saying. In particular, Hillary Clinton said that Donald Trump, in the interview with the Washington Post had said that the US should play a lesser role in NATO, which has been the bedrock of the Transatlantic Security relationship for decades and NATO is based in Brussels. So, he took a lot of criticism for that, and people said, well hold on a second, NATO's operating in Afghanistan, it's tacting (sp?) terrorism that way.

SEVASTOPULOIf you really care about stamping out the threat, you shouldn't be talking about reducing the US role.

LANPHERWe have an email from Kay in Silver Springs. Why is no one acknowledging that however terrible the attacks in Brussels are, they are a pale shadow of what people in the Middle East and parts of Africa live with all the time. Starting with 9/11, the reactions in the West have always seemed to be that we have the right to be safer and more comfortable than the rest of the world. I think the message is that Western safety and comfort are going to have to be shared. Demetri.

SEVASTOPULOIt's a fair point. I mean, the reason why all these attacks in Paris and Brussels are getting huge attention is, until recently, they weren't happening. So, all of a sudden, a society that was used to a stable life and security feels threatened. If you grew up in a country, for example, as I did in Ireland, where we had terror threats all the time during the IRA campaign, you become immune to it, as terrible as that sounds. And I think if you're in a country like Turkey where they have a lot more incidents of violence and of terrorism, you become immune to it.

SEVASTOPULOThe West is, with this homegrown terror threat in Belgium and France and, you know, some people say that it exists in the US too, although, really, there's been very little evidence of that. You have societies are starting to become very scared.

LANPHERI don't want to get us too far off path, but certainly, there is always some conversation when we have a mass shooting and whether you consider that terrorism or not. And the fact that it's random, you don't know when it's going to happen.

SEVASTOPULOWell, even if you don't call it terrorism, and people will debate that until the cows come home. If you think...

LANPHERI hear them. Yes.

SEVASTOPULOOr pigs fly.

LANPHERYes.

SEVASTOPULOIf you think that there's been fewer than 100 people have been killed on American soil from terror attacks since 9/11, that's 15 years ago. Less than 100 people. Mark probably knows the exact number. There will be 10,000 people killed in America this year from gun violence and that doesn't include people who kill themselves with guns, suicides. 10,000 people.

LANPHERMark.

MAZZETTII think it's also important to sort of see, you know, the question of why Europe? Why now? You can't detach it from this overall campaign against ISIS and what the Islamic State wants. I think too often, we say, well, there's this bombing campaign going on in Iraq and Syria and there's this terrorism problem going on in Europe and elsewhere. When, in fact, they're all part of the same phenomenon. The United States and coalition countries are bombing, pretty relentlessly, Syria and Iraq to get at the Islamic State's headquarters. What is the Islamic State's response?

MAZZETTIWell, their response is to score victories of their own in the capitals of Europe. They are seeing vulnerabilities in Europe because of everything we've discussed earlier. Intelligence agencies that don't talk to each other, borders that don't really exist in Europe. And quite easily, building up networks to do these attacks, they, this is their response, in many ways, to what is happening in Iraq and Syria.

LANPHERNora.

BENSAHELYeah, and the campaign is not going well for them at the moment in Iraq or Syria. You know, compared to the high point in the summer of 2014, when they controlled the most territory they ever have, ISIS has lost 40 percent of that territory in Iraq and 20 percent of its territory in Syria. The city of Ramadi has been retaken. Mosul may be next. So, they really are being very much squeezed, you know, in the place where they control territory and, you know, it's the heart of where their activities are.

BENSAHELSo, being able to claim credit for these kinds of attacks, even though, you know, they -- the exact degree that that network was affiliated with the folks on the ground in Syria and Iraq is still very much unknown. This helps their propaganda, because it enables them to show a success when they're clearly being defeated in certain ways on the ground in the Middle East. And they can claim that they're taking the fight to their enemies, which is, you know, the rally around the flag effect, you know, that you might see in the US, for example, when the US goes to war. This is part of what they're trying to do around their own flag of the caliphate, self-proclaimed caliphate that they've established.

LANPHERI'm just -- this just came in from our producer. CBS News reporting that at least a dozen Americans were injured in the Brussels attacks. And the State Department is still accounting for others, including US citizens. But again, this is not going to have much of an impact at the polls.

ELVINGIt may have its impact in subtle ways.

LANPHERRon Elving.

ELVINGIt may, it may affect the way that people feel as they're going, but let's look at it in terms of the practicality of the way these primaries are held. We have two weeks now, before there's another primary in the Republican Party. We have two weeks before there's another primary in the Democratic Party, except they have caucuses this weekend in Alaska, Hawaii and Washington state.

LANPHERIs it all right for us to breathe a sigh of relief that there's two weeks off?

ELVINGI can't imagine anyone covering this campaign who is not breathing a sigh of relief and, you know, perhaps reintroducing themselves to their family and loved ones. But this is a moment at which we might all have some degree of pause. I think a lot of Republicans are hoping to regroup and decide how the anti-Trump strategy may go forward. I'm sure that the Sanders forces are looking for some victories this weekend in some of these caucus events, as they've done very well in caucus events.

ELVINGBut the issue does not necessarily play perfectly for any of the Democratic candidates, and it is something of a struggle, at this point, to see which of the Republican candidates, that is Trump or Cruz, can be Mr. Anti-Terrorism. John Kasich has actually sounded quite moderate in comparison to the other Republicans and very much more like the two Democrats.

LANPHERI have one quick thought on that, but first, Demetri, the Republican wallflower, John Kasich. Where is he in all of this?

SEVASTOPULOWell, John Kasich, at last count, I think hit 143 delegates. So there's no way he can win the ballot at the first vote at the convention. John Kasich is hoping that neither Ted Cruz, or more importantly, Donald Trump, will have 1237 delegates. There will be a contested convention, he will be seen as the moderate Republican who has the best chance of beating Hillary Clinton. And frankly, the polls right now, if you believe them, we're still a way away from the election, actually say that.

SEVASTOPULOAnd that the establishment would rally behind him. But the fact that Mitt Romney, Lindsay Graham, who backed Jeb Bush after he got out of the race himself, and Jeb Bush are supporting Cruz makes Kasich's path, I think, a little more difficult.

LANPHERAnd we have an email from Trevor in Indiana, which speaks directly to this. If these leaders of the GOP continue to endorse Cruz and he ends up losing this fall, will these failed attempts to stop Trump only cause further discord within the party?

SEVASTOPULOWell, the Party right now, it's not as fractured as the Democratic Party, which is kind of an umbrella organization of different groups. The Republican Party, right now, broadly speaking, is two strands. You have the mainstream Republicans who are not particularly bothered with social issues and some of the more conservative ideals and then you have the kind of Ted Cruz Republicans, who are much, much more conservative. They have long argued that the reason the Republicans struggle to win the White House is that they never put forward a true conservative.

SEVASTOPULOAnd George W. Bush was the closest they got to that. So, there's a wing of the Republican Party, the establishment now, who says why don't, if it's between Trump and Cruz, why don't we push for Cruz. He will win -- excuse me, he will lose badly and it will cleanse the party of that view. And we will become a more moderate, modern Republican Party that doesn't worry about gay marriage, doesn't worry about some of these social issues. Which frankly, their younger members aren't talking about.

LANPHERI think I remember hearing that argument when Romney was the candidate, that, that we would -- cleanse is just not a good verb these days.

SEVASTOPULOBut this time, you have -- but Romney was the candidate, whereas this time, you have either Trump or Cruz. The establishment candidate, the closest -- the only one in the race is John Kasich and he's not polling anywhere in the Republican primaries.

LANPHERI'm gonna go to another caller. This looks like another political question. This is Joyce calling from Raleigh.

JOYCEHi. If there are super delegates representing votes in caucuses, it's my understanding, in Utah, Bernie Sanders got 70 percent of all those voting in the caucus. What percent of the super delegates who represent the establishment and are not elected, did Bernie get and what percent did Hillary get?

ELVINGWell, that's not how super delegates work. Basically, super delegates are not determined by the vote in their states. That's why they're different. That's why they're sometimes called super and sometimes called less flattering things. Because some people consider it un-Democratic and I suspect, perhaps, the caller considers it un-Democratic to let people from Utah and Idaho, where, as she says, the vote was overwhelmingly for Bernie Sanders, decide on their own because that is what they are empowered to do, given their unpledged status, by virtue of their office.

ELVINGEither elected office or party leadership office to go to the convention and vote any way they want. Now, they can be fickle. They can say they're for Hillary and then turn around and be for Bernie. Or, they can go the other way. But as of right now, we have 467 super delegates saying they're voting for Clinton and only 26 for Bernie Sanders. That's nationally.

LANPHERI'd like to go to Mark Mazzetti for just a moment and do a practical question, which is how safe are US airports?

MAZZETTII think in terms of airports within the United States, there's very little debate that security in the 15 years since the September 11th attacks is far better. It is pretty tough to get into this country on a plane. And even when you're in an airport, it is pretty secure. Now, that would not stop someone who was in this country in a city driving to an airport and shooting it up. If, as we all know, guns are plentiful in this country. So, just because you're at an airport doesn't mean you are entirely safe. But in terms of the threats that we worried about 15 years ago with airport security and terrorism, those are far diminished.

LANPHERAll right. You are listening to The Diane Rehm Show. We want to remind you that there's still a chance to be part of this conversation. 1-800-433-8850. Drshow@wamu.org if you'd like to send an email. Our website is www.drshow.org. Let's get another quick call in here. Let's go to Carl who's calling us from St. Louis. Hey Carl.

CARLHi. Hi. Yeah, I have a question about the differences between caucuses and primaries. And I guess it seems like Bernie's successes in the caucuses are being discounted, largely. I went up from -- you know, in Missouri right now, but I went up to -- with my kids, we home school, up to observe the caucus processes in Iowa and it seemed like there was a lot of influence from the Party, the Democratic Party, in that case. We went to the Democratic caucuses there. And then also, all the paid precinct captains from Hillary's side. And it seemed like there's a lot -- if you have a lot of money and organization and the backing of the Party, that there's -- in the caucus process -- in the processes, in the caucus process, you have a lot of advantage.

CARLAs far as when you actually -- when they open and close the doors, how they -- there's a lot of gray, subtle areas in, when they're assigning delegates. I mean, I witnessed this myself firsthand. I wasn't voting. I was just observing it with my kids.

LANPHEROkay.

CARLAnd, you know, he, he -- I think it's pretty clear. He took, I mean, he won Iowa and all these states, he's so close, and yet, he's just being discounted left and right.

LANPHEROkay. Demetri.

SEVASTOPULOWell, I'm not sure that he's being discounted. I mean, he's -- where he's won those states in the caucuses, he's got the delegates. And I think he's actually done well in the caucuses because those states or those contests, they benefit candidates who have very passionate supporters. Because to caucus, you have to spend a lot more time at the polling station, several hours in the case of Iowa whereas in a Republican caucus, you go in and vote. It's a much shorter process. So his supporters, I would say, are more passionate than Clinton's supporters. And therefore, he does well in the caucuses. There just aren't enough of them for him.

LANPHERI believe our caller incorrectly stated that Bernie won Iowa. But...

ELVINGHe, he was the winner in the minds of many of Sanders' own supporters, because it was very close. It was extremely close. And they felt that some of the delegates had been determined on coin flips in a few of the precincts and so on, and that they had been shortchanged if not done dirty by that entire process. Now, the way it works is the Iowa process is still going on. They began back in February with the precinct caucuses and then they go to county, then they go to Congressional district. And then they go to a state convention.

ELVINGAnd let me just mention that this weekend, in Washington state, they will begin at the precinct level and something somewhat similar to the Iowa arrangement and the precinct caucuses around the state will elect 27,000 delegates who will then go on to a May 1st caucus at the legislative district. And then county conventions and they'll narrow that down to a mere 1,400 delegates. And then, later on in May, at the Congressional District level, they'll narrow that down to 67 delegates who will actually go to the national convention.

ELVINGNow, in that kind of process, yes, precinct captains and having some organization should be an advantage. But, in fact, Bernie Sanders has been quite dominant in the caucuses. That is really where he's been getting his delegates and it is also possible in the delegate states to get disproportionate numbers of delegates relative to the share of the vote. And that makes it much more advantageous and efficient as a way to build up the Bernie Sanders showing.

LANPHERWe are going to have to -- we're nearing a close here. So, I'd like to give you each an opportunity to talk about what might be ahead. Both in this investigation and in the upcoming, well, in the two week pause we have before what's coming next. Demetri, I'm going to start with you.

SEVASTOPULOWell, I think in the election, on the Republican side, where there's, you know, a lot more curiosity about what's going to happen in the race, I would say, everyone's looking ahead to Wisconsin. The Republican establishment has two weeks to try and build up the anti-Trump campaign. Will it be successful there?

LANPHERThat's Demetri Sevastopulo, Washington Bureau Chief for the Financial Times. Nora Bensahel at American University School of International Service.

BENSAHELI think there's still a lot to be learned about what happened in the terror attacks yesterday, particularly the connections to the attacks in November in Paris and how much they were influenced by what's going on in Syria and Iraq.

LANPHERMark Mazzetti, National Security Correspondent for the New York Times.

MAZZETTINot to be overly depressing, but to Nora's point, I think this is more -- there's more to come here. I think the vulnerabilities we've all discussed in Europe, the intelligence services lack of sharing, ISIS now sees its gains and victories and there are more to come.

LANPHERRon Elving, the NPR political pro, in seconds, please.

ELVINGThe trajectories are clear in both parties towards these nominations, at this point. But the national security issue is over clouding all and could still be dispositive as we get closer to the conventions and then to November.

LANPHERI'm Katherine Lanpher, sitting in for Diane Rehm. Thank you for joining this conversation and thank you to all of our panelists.