MS. DIANE REHMThanks for joining us. I'm Diane Rehm. Earlier this week, the Islamic State was forced to give up control of the ancient city of Palmyra, the latest indication the group is weakening in its control of parts of Syria and Iraq, but there are no signs it intends to let up on terrorist attack elsewhere, the latest being suicide bombers in Brussels, who killed 34 people earlier this month.

MS. DIANE REHMJoining me to talk about the Islamic State and what it means for the future of the Middle East, Aaron David Miller of the Woodrow Wilson International Center. Joining us by phone from London, Fawaz Gerges of the London School of Economics. And from an NPR studio in New York, Michael Weiss of The Daily Beast. Your calls, comments are always welcome. Join us on 800433-8850. Send us an email to drshow@wamu.org.

MS. DIANE REHMFollow us on Facebook or send us a tweet. And thank you all for being with us.

MR. AARON DAVID MILLERDiane, thank you.

MR. MICHAEL WEISSThanks very much.

REHMMichael Weiss, you've written a book titled "ISIS: Inside The Army Of Terror." Can you tell us about the allegations that some people are making that ISIS is actually on the defensive at this point?

WEISSWell, I think it's certainly true with respect to the war in Iraq and Syria. They've lost, depending on who you ask, the Pentagon estimates 40 percent of the territory they held as of June 2014. I think that estimate might be a little bit high. IHS Jane's Defence, a British defense firm, reckons it's more like 22 percent. But regardless, they are losing more ground then they're gaining, which is a good thing. But that is confined to the battlefield within the so-called caliphate.

WEISSWhen it comes to foreign operations, terrorism abroad, they're very clearly not on the defensive. They're on the offensive. And this is the result of an edict that was given by Abu Mohammed al-Adnani, the spokesman of ISIS. In fact, he's really more like the number two in the organization. He runs all of Syria for the terror army. And he said, in 2014, just before, actually, the siege of Kobani -- you remember the Turkish town on the border of Turkey -- the Kurdish town, excuse me, on the border of Syria and Turkey.

WEISSHe basically said, look, now is the time to take the fight to the West, to kill the kufar wherever you find them. If you can find a rock, pick up the rock and smash his head in. If you have a car, drive over him with the car. This was essentially a global casting call for foreign jihadist attacks everywhere and anywhere. And, you know, of course, you then saw a proliferation of these attacks in Turkey, Beirut, the Metro Jet bombing above the skies in Sharm el Sheikh, Egypt.

WEISSThen, of course, the dastardly massacre in Paris and Brussels. What is happening now, and based on my reporting and interviews with ISIS defectors, who've recently left the organization, you have the -- this group is essentially bifurcating. There is a domestic wing, which is still running the insurgency in Syria and Iraq, fighting, conducting suicide bombings, terrorism in Baghdad or, you know, in parts of Aleppo or whatever.

WEISSAnd then, you have this growing foreign arm. And what is interesting about the foreign arm is it is increasingly being lead by Europeans, not by native Iraqis or Syrians. It's important to remember, Diane, that ISIS, although it began in 2004 as a foreign jihadist-lead endeavor -- it was headed by a Jordanian called Abu Musab al-Zarqawi. By about 2006, 2007, the upper echelons of the organization were populated by Iraqis. And today, a lot of those Iraqis in the top structures of ISIS are former members of Sadam Hussein's Ba'ath party regime.

WEISSSo they had always put a premium, in the latter half of their existence, on having this be an Iraqi-run enterprise. That is now changing, at least with respect to carrying out these foreign operations. And you see a lot of francophone fighters from France and Belgium. There's a guy called Salim Bengolum (sp?), who has now become the head of European operations. So any terror attack that is perpetrated on the continent will have some tie to this guy.

WEISSAnd I know that U.S. intelligence, French intelligence are gunning for him. There's other people who are responsible for planning or coordinating the Paris massacres who are essentially being promoted by Baghdadi, the head of the organization, as a reward because they know that culture. They come from this part of the world and therefore, they are most adept at planning future attacks.

REHMAnd now, turning to Fawaz Gerges, he is at the London School of Economics and author of a brand new book titled "ISIS: A History." Fawaz, you've been listening to Michael Weiss. You know that apparently the Islamic State was reportedly forced to give up control of the Syrian city of Palmyra. How much territory have they actually been forced out of and to what extent? Does that link itself to the kinds of terrorist attacks we've seen in Europe?

MR. FAWAZ GERGESWell, I mean, hello, Diane. It's a pleasure to be on your show today.

REHMThank you.

GERGESI mean, in Iraq, we estimate that the so-called Islamic State has lost between 40 percent and 50 percent of the territories that it controlled since 2014. In Syria, it's very dynamic because ISIS or the so-called Islamic State controls about 50 percent of the Syrian territory. We estimate that it has lost about 20 or 25 percent of its territories in Syria, in particular the Syrian Army and its allies succeeds in basically dislodging ISIS from not just Palmyra, but even the territories around Palmyra which represents a huge desert area all the way from the Syrian territories to the Iraqi border.

GERGESMy take on it is that in the next five or six months in Syria, you're going to see the territories controlled by the Islamic State shrinking all the way to Raqqah. In fact, there's a race now to Raqqah between the U.S.-lead coalition, which has basically created a coalition of the Kurds and other Syrian oppositional forces and the Russian coalition lead by the Syrian Army and Hezbollah and its Iranian counterparts.

GERGESBut I think more important than these territories, Diane, the so-called Islamic State is bleeding, is squeezed, is on the retreat. It not only has lost quite a big chunk of its territories, it has lost more than 15,000 skilled fighters. It's ability to recruit fighters has been reduced dramatically in the past six or seven months as a result of American actions, in particular, with Turkey. The narrative, which is much more important, I would argue, than the physical fight, the narrative of ISIS that it's invincible, undefeatable, standing tall, winning, I think a major nail has been hammered in this particular narrative as a result of the losses in Iraq and Syria.

GERGESAnd I think, all in all, I don't think we have witnessed the beginning of the end of ISIS that we might be seeing quite a major retreat, a major, basically, regression in the fortunes of ISIS in the next few months.

REHMAll right. And now turning to you, Aaron David Miller, you heard Michael Weiss refer to a growing foreign army lead by Europeans. So is ISIS reinventing itself with a European force even as Fawaz says it is shrinking in Syria and elsewhere militarily?

MILLERI mean, I think that's the paradox, Diane, and Michael knows this well, that is, ISIS suffers defeat in the so-called caliphate, out on the battlefield. Its capacity and determination are projected to influence its power into recruits paradoxically actually expand. And it's not as if ISIS, the Islamic State, all of a sudden, discovered foreign terror as a device to mobilize constituents. I mean, Abu Musab al-Zarqawi, we recall, in 2004, all along this has been a part of ISIS' message.

MILLERYou remember the hotel bombings in Amman, Jordan, against Western hotels and Westerners. So I think this is important. It also feeds, I think, on a ready-made constituency. The reality is that these are first generation citizens of the European Union alienated, disenfranchised, struggling with their own identity, many small time petty criminals intersecting with the jihadi narrative, vulnerable to this sort of recruitment.

MILLERAnd European counterterrorism, both because of the political culture and the realities that they're overwhelmed are simply not prepared to deal with this reality. I mean, Molenbeek, 100,000 people, second poorest community -- second largest community, second youngest, second poorest community in Belgium, you know, eight of the 114 imams don't speak any of the Belgian languages. So you're dealing with a readymade pool of recruitment that's going to provide a long term problem in the fight against ISIS.

REHMAaron David Miller, he's at the Wilson International Center. He's the author of the new book titled "The End of Greatness: Why America Can't Have And Doesn't Want Another Great President." Short break, right back.

REHMAnd welcome back. We are talking about ISIS, the current state thereof, what it is trying to do throughout not only the Middle East but Europe and the U.S., as well. Joining us from London is Fawaz Gerges, he's professor and chair of the Middle Eastern Center at the London School of Economics and author of "ISIS: A History." Aaron David Miller is vice president, distinguished scholar at the Woodrow Wilson International Center. And Michael Weiss is senior editor of The Daily Beast, co-author of "ISIS: Inside the Army of Terror."

REHMFawaz, if I could come back to you, the Islamic State grew out of al-Qaeda. How did ISIS eclipse al-Qaeda?

GERGESYou're absolutely correct. Al-Qaeda central and ISIS belong to the same family. And the family is called Salafi jihadism or the global jihadist movement. We all remember that there we no al-Qaeda in Iraq before the U.S. led the invasion in 2003. Al-Qaeda in Iraq grew in the aftermath of the chaos created by the U.S.-led invasion and the armed resistance that existed in Iraq. And we know that Abu Musab al-Zarqawi and his subsequent lieutenants, including Abu Bakr al-Baghdadi, the current leader of ISIS or the Islamic State, basically swore bay'ah or fealty to Osama bin Laden.

GERGESI think the struggle between the Islamic State and al-Qaeda grew out of a fierce rivalry in Syria between 2012 and 2014 because Abu Bakr al-Baghdadi, the leader of the so-called Islamic State, sent his own men to Syria. They established a front called Jabhat al-Nusra or Al-Nusra Front, and Al-Nusra Front became much bigger than the Islamic State in Iraq itself, and Abu Bakr al-Baghdadi realized that the leader of al-Qaeda in Syria, or Jabhat al-Nusra, Abu Mohammad al-Julani, basically was on the brink or on the verge of eclipsing Abu Bakr al-Baghdadi.

GERGESSo he basically decided, or he ordered Abu Mohammad al-Julani, the leader of Jabhat al-Nusra, to basically dissolve Jabhat al-Nusra and merge with the so-called Islamic State in Iraq. So it is at the end of the day, the big point to highlight is that the jihadist movement, the Salafi jihadist movement, basically have many cleavages. They are as divided as the existing Middle Eastern regimes. Here is the irony, Diane, in Iraq and Syria. There was one Ba'ath party in both Iraq and Syria from the 1960s up to, you know, 2003. Yet both the Ba'ath parties really engaged in a fierce rivalry for power, for influence, for prestige.

GERGESAnd now you have al-Qaeda in Syria, led by Jabhad al-Nusra, and you have the Islamic State, which is basically an Iraqi-based movement. They are also fighting for territory, they're fighting for prestige, they're fighting for power and for influence. Another big point to really take out of this particular rivalry between al-Qaeda central and its affiliates and the Islamic State is that there is a major conceptual difference between the two groups. Al-Qaeda central has always focused on the far enemy, the United States and its European allies. The so-called Islamic State, its focus is mainly on the near enemy, Syria, Iraq, Saudi Arabia, Jordan. That is basically it's strategic prize is at home.

GERGESAnd here a point I want to make, final point, please don't be misled, don't be blinded by the new focus, technical shift of the Islamic State into the heart of Europe, where I live, either in Belgium or France or England. The strategic prize of the Islamic State is the near enemy, Iraq, Syria and the Arab heartland, even though recently it has devoted more resources to attacking Western targets, including American targets. But these are a diversion from the strategic focus.

REHMInteresting.

GERGESThey are painful, they are insidious, they are dangerous, but the strategic, central, key goal of the Islamic State is to establish either a caliphate or Islamic state in the heart of the Arab world, not to really defeat other European countries or the U.S., even though we have to be concerned about the technical shift by the Islamic State in the last six of seven months into Europe and the Western world at large.

REHMMichael Weiss, would you agree?

WEISSBroadly I would, although I would add that when it was al-Qaeda in Iraq, there were abortive attempts to perpetrate terror attacks in Europe. The Zarqawi network was working very assiduously to do essentially what the al-Baghdadi network is now able to do. I always am a little bit reluctant to say that this is a new strategy or tactical shift. It's what I would call the new old strategy. There's a renewed emphasis on foreign operations, for reasons we got into in the last segment.

WEISSThey are losing the narrative with respect to controlling territory. Remember June 2014, or by July 2014, they were able to say with total legitimacy that they were in control of a swath of geography roughly the size of Great Britain. I mean, that was a huge, galvanizing recruitment tool, and it was central to their propaganda. As the territory shrinks, and by the way their internal media is like Pravda, they deny that they're losing anywhere on the battlefield, they still claim that they're in control of Tikrit, for instance, in their daily newsletter that is distributed in Al-Bab, one of the two main towns in Aleppo they still control.

WEISSBut as they shrink on the battlefield, they are going to re-up and revivify this foreign attack wing. And as I mentioned, you know, the idea that Europeans, and by the way, Diane, I don't mean Europeans who are first-generation, you know, Muslim immigrants, from Arab or North African countries in Paris and Belgium, I mean people who were born, you know, white Frenchmen.

GERGESIn Europe, yes.

WEISSYes, and do not necessarily even come from an Islamic background, who converted, are now in Syria, are being looked to and deferred to in a way that is really unprecedented for this organization. I mean, the analog, I suppose, with al-Qaeda is the Adam Gadahn, who was an American convert to Islam who became essentially the spokesman or chief propagandist in chief for bin Laden. I mean, he's still alive somewhere in Waziristan or God knows where.

WEISSBut anyway, this is what they're doing. They're also, as Fawaz was saying, there is this competition. You know, the patron and the subsidiary have split, and as a result, there is both a cold and hot war now being waged between ISIS and al-Qaeda. On the battlefield in Syria, Nusra was one of the main anti-Assad or opposition groups to actually rise up against ISIS in January of 2014, effectively booting them out of Idlib and most of Aleppo Province.

WEISSNow you see every time there is a terror operation waged by al-Qaeda abroad, and by the way, when we say abroad, and here's where I also agree with Fawaz, you have to put the initial concentration on the region itself, Tunisia, Saudi Arabia, the countries, the Gulf Arab states, Turkey, which has suffered the most terrorist attacks by ISIS in the last 18 months. Every time there's an ISIS operation waged abroad, it's almost always soon followed by an al-Qaeda operation.

WEISSAnd look, there is some interleavings between these two organizations. We like to think in, I think, overly codified categories. You know, al-Qaeda is Column A, ISIS is Column B. Oftentimes fighters will migrate from one organization to the next. There is a fluidity because, you know, they are trafficking in the same ideological currents of Salafi jihadism. Although the long-term ambition is the same, ISIS has essentially declared statehood well in advance of whatever al-Qaeda has conceived of as a viable timetable.

WEISSBut regardless, this is what makes this so dangerous because right now, we are at a more dangerous point in terms of international terrorism than we were right after 9/11 or even frankly during the Iraq War. You have two very, very powerful organizations that are recruiting, and they are recruiting abroad, it doesn't matter if they're suffering battlefield defeats in Syria and Iraq, recruiting to outdo each other and to outperform and to steal each other's thunder.

WEISSAnd the way they're doing that is in blood and carnage on the streets of Western capitals. It's quite right, they do not think they're going to, despite the propaganda, one day we will conquer your realm. I don't think they ever see themselves with advancing columns marching down Pennsylvania Avenue in Washington, D.C., but that's not the point. The point is, and this is the classic definition of terror, to discombobulate, to traumatize and to alter the Western political systems, right, to make Muslims in the West feel completely disinherited and disenfranchised.

WEISSThere is two options, the land of disbelief and the land of belief. You come to the land of belief. If you cannot make that journey, then you must attack in the land of disbelief.

REHMAaron?

MILLERYou know, Fawaz' point and Michael's clarification is critically important, I think. This isn't World War II, and this is something I think that the fight -- those who fight and combat terror have to understand. ISIS may well present a major threat to international security, but the fierce urgency of now, getting the international community to become risk-ready, not risk-averse, to become united rather than separately interested in their own agendas, this is critically important.

MILLERISIS is not threatening to take over Western Europe or large parts of Asia, and it's not for nothing that the international community has failed to coalesce. And that's the critical problem, I think, both in the European context but more important in the region. ISIS is a symptom and a product of a broken, angry and dysfunctional Middle East, where no governance, bad governance or dysfunctional governance is creating fertile territory.

MILLERAnd this brings me to the final point, which is the quote-unquote long war. We are 14, 15 years now September of 2016, after 9/11, and yet al-Qaeda has not been fundamentally destroyed. It's evolved, and it's morphed, and that's the critical question. How do we measure time with respect to success in this long war?

REHMYou have said, Aaron, that Syria will be viewed as President Obama's biggest policy failure because he chose not to put troops on the ground. Is the growth of ISIS and the operations of both al-Qaeda and ISIS directly connected to the U.S. refusal to engage?

MILLERI mean, I think this is a critically important question. You know, I've worked for Republicans and Democrats. I've voted for Republicans and Democrats. You know, the dividing line for me is not between left or, right, liberal/conservative or Democrat and Republican. It's between dumb on one hand and smart on the other. And the only thing that matters is which side of the line you want America to be on.

MILLERWe could spend the next hour trying to figure out who to blame for this. Was George W. Bush too risk-ready in invading Iraq and creating the grounds of an insurgency that produced ISIS? Was Barack Obama too risk-averse in getting out of Iraq too quickly, not recognizing the Syrian threat? The reality is America does play a role and has in the rise and the emergence of this kind of jihadi terror. But I refuse, and I may be one of the last-standing human beings in Washington, I refuse to accept the notion that the United States is either the fundamental cause or the driving catalyst for the emergence of these organizations.

MILLERThis is on the Arabs, the Arab states, the dysfunctional governance, the debate within Islam that has not yet been resolved, the refusal, I think, to delegitimize extremists, even though there are growing efforts in this regard, within their midst. And the U.S. is a player and deserves a measure of responsibility, but this is not on us.

REHMAnd you're listening to the Diane Rehm Show. Michael Weiss, to what extent do you see the U.S. having, by virtue of not moving into Syria, having played a role in the growth of ISIS?

WEISSWell, there is no question -- I mean, let's rewind the clock a little bit. As of 2009, certainly 2010, al-Qaeda in Iraq was not completely eliminated and annihilated. I don't think these groups can ever categorically defeated in that sense. But they were strategically defeated. They had been routed by the so-called Anbar awakening, which was solidified -- that was a grassroots uprising by Sunni Arab tribal actors who had at one point partnered with and become accomplices to the al-Qaeda resistance against the United States. and then turned against them for various reasons, not least of which is al-Qaeda started to steal all the money, by which these tribal actors had subsisted and remunerated themselves for hundreds of years, money, by the way, that was often legal and sometimes not so legal.

WEISSSo they saw the United States not as a liberating force but as a more credible intercessory force, a non-sectarian actor that once routed terrorists from cities such as al-Fallujah or Mosul, didn't go around doing pogroms and ethnic cleansing. This the great fear of Sunnis, that, you know, the cure might be worse than the disease. So al-Qaeda in Iraq was strategically defeated, and there was meant to be a political process by which these tribal actors, who became essentially neighborhood watch squads and volunteers going after jihadis, were to be integrated into the Iraqi political system.

WEISSThat did not happen because Nouri al-Maliki was a sectarian thug and a henchman of Iran, and despite that, and despite the intelligence at the time, the United States backed him for re-election in 2010. Now we can re-litigate that election, but he did not win it fairly. In fact, he violated the Iraqi constitution, which we helped write for the Iraqi government, in order to reclaim the throne in Baghdad. And we forget this.

WEISSBut as of 2011, several things happened, not least of which, the big one of course is the Syrian revolution. But at the same time, there were protests taking place by Sunni communities in Iraq that were suppressed, and I don't mean suppressed in the sense of, you know, water cannon. There were gunfire battles, people were being rounded up, Sunni politicians were being interrogated, accused of terrorism. The vice president of Iraq was driven out of the country, into exile in Turkey, and, you know, the dispossession and marginalization of the Sunni political class essentially opened the door for AQI's return.

WEISSIn Syria, and this is something -- this is an occluded history that needs to be properly understood. For the better part of the U.S.-led occupation in Iraq, the Bashar al-Assad regime was one of the world's leading patrons and sponsors and underwriters of al-Qaeda terrorism in Iraq. Jihadis would come from around the world, they would land at Damascus International Airport, they would be met by some (unintelligible) fixer, they would be ferried into the Jazeera, into Eastern Syria, kept in a safe house overseen by some border emir run by al-Qaeda and then dispatched across the border to join what was then this swelling insurgency.

WEISSThis relationship, this proxy relationship, continued all the way until 2009. We know this because there was a very good Iraq intelligence officer who had an agent in a meeting in Zabadani, a town about 40 miles north of Damascus. At that meeting were three different groups. One was the Iraqi Ba'ath insurgents, because remember the insurgency isn't just jihadi. The other was al-Qaeda in Iraq, and the third was the Syrian security forces. All three planning terror attacks not even against U.S. targets in Iraq but against Iraqi state institutions.

REHMAll right.

WEISSThe Maliki-led government. So Assad has a lot...

REHMWe've got to take a short break here. When we come back you'll hear more and our callers. Stay with us.

REHMAnd welcome back. It's time to open the phones. Our guests here, Fawaz Gerges, he's on the line with us from the London School of Economics, Aaron David Miller is of the Woodrow Wilson International Center, Michael Weiss is senior editor of The Daily Beast, all of whom have extraordinary, in-depth knowledge about what is going on in this world of ISIS, al-Qaeda and the world of terrorism.

REHMLet's go to Nino in Chapel Hill, North Carolina. You're on the air.

NINOHi Diane.

REHMHi.

NINOIt is great to have you back.

REHMThank you.

NINOI would just like to correct Aaron David Miller. It's second-generation Muslims in the West who are coerced into radical Islamism, not first-generation. And the point there, because their knowledge of Islam didn't start in Pakistan or Sri Lanka or even Palestine, but in Islamic centers and mosques that are sponsored and financed by Saudi Arabia.

REHMAll right, do you want to comment on that, Alan David Miller?

MILLERDiane, I think that's right. I mean, as far as Saudi sponsorship, I think therein lies another anomaly and a huge challenge. You have states, petro-states like Saudi Arabia, over the years sponsoring Salafi religious education in places like Afghanistan and Pakistan. And while Saudi Arabia isn't ISIS, the general climate and political ideological helps to sustain the notion that Sunni Muslims are somehow triumphant, exclusive and superior, and that does in fact lead to this sectarian tension, which the Saudis are only too willing to exploit and which ultimately may come back to haunt them.

REHMAll right, let's go to Columbus, Ohio. Reema, you're on the air.

REEMAYes, hi, thank you for taking my call.

REHMSurely.

REEMAThe situation started -- I agree with one of your guests completely -- that created a vacuum in the Middle East with the war in Iraq. And now when Syria rose, they created another vacuum when they did not act on taking Assad out and helping the Free Syrian Army, who are the Syrian people who wanted their freedom and the democracy. And if, you know, if they had done something, we would not have been in this situation now. And I have to tell you, Assad is part of ISIS. ISIS created because Assad said to the world if I go, this is what you're going to have.

REEMAThe truth is he never, ever hit them. He never bombed them. Even Russia, when they came, they did not even bomb ISIS, and they use them to their propaganda, and this is why we cannot -- we cannot take ISIS out unless we take Assad out.

REHMAll right, Fawaz, do you agree with that?

GERGESWell first of all, I really would like to stress a critical point about the fact that there is no single driver. There is no single cause that explains either the rise and the growth of the global jihadist movement, of which both al-Qaeda and ISIS are two members of this family. What we need to understand, and this is to your listeners, Diane, is that social phenomena are very complex and require complex explanations. But this brings me to the central point that the U.S. has played a critical part, unwittingly and indirectly, in the rise of this particular movement.

GERGESThis does mean that the United States is fundamentally responsible or solely responsible for the rise of the global jihadist movement, including al-Qaeda and ISIS. Quickly, al-Qaeda central of Osama bin Laden, Ayman al-Zawahiri, is a product of the Cold War, the global rivalry between the United States and the Soviet Union and the killing fields of Afghanistan. Afghanistan was a critical theater for the rise and the spread of this particular ideology. In the same way, no one can deny ever that ISIS or basically -- which basically is a product of al-Qaeda in Iraq, and President Barack Obama acknowledged this fact, that he says that ISIS is basically the unintended consequences of the U.S. invasion and occupation of Iraq and also the spreading sectarian and ideological chaos both in Iraq and Syria.

GERGESThis is a fact. But the big point here, having said -- made -- put this particular point on the table, I would argue that the rise of the Salafi jihadist movement, including both al-Qaeda central and ISIS and the various affiliates, are the product of an organic crisis in the Arab Islamic world. What I mean by organic crisis, it's fundamentally a developmental crisis, an institutional crisis about broken institutions, about political authoritarianism, about abject poverty, about tyranny, about a constant foreign intervention.

GERGESAnd Assad, when we talk about Assad and Iraq, we're talking about -- we have never mentioned a word about the Arab Spring uprisings and how the derailment of the Arab Spring uprising -- remember, Diane, 2010, 2012, millions of Arabs, millions of Muslims came out on the streets for dignity, for justice, for freedom, universal values. There were no black flags. There were no calls to establish Islamic states, about universal values, about citizenship, about reclaiming the state from -- I mean, authoritarian leaders.

GERGESAnd what happened subsequently in Syria and Iraq and the counterrevolutionary forces really provided these nihilistic movements, not just al-Qaeda and ISIS but even non-state actors, broadly defined, with the ideological ammunition that have allowed them to grow and spread in the region. So just a point really is it's not just America. It's not just Saudi Arabia. It's not just Assad. It's multiple drivers and causes that basically really have brought about a rupture, a social rupture...

REHMIndeed.

GERGESAnd allowed ISIS and al-Qaeda to fill a vacuum, institutional vacuum and also a vacuum of ideas.

REHMIndeed.

GERGESThere is no big idea that basically competes with the al-Qaeda central or the Salafi jihadism.

REHMAll right.

GERGESIn fact, Abu Bakr al-Baghdadi is saying to the world, I have an idea, and the idea is a caliphate. What are the other ideas that are competing with Abu Bakr al-Baghdadi? Militarism and mainstream Islamism. So it's a crisis, organic crisis, developmental crisis, institutional crisis. Even if America disappears tomorrow, this particular crisis will continue to ravage the Arab Islamic world at this historical moment.

REHMAll right, and we have an email from Sameeta, who says, who is the financing the ISIS attacks in Europe? Michael Weiss?

WEISSWell, since 2006, ISIS or al-Qaeda in Iraq as it was then known, has been self-financed. You know, this one of the sources of great mythology, what shadowy figure, what sinister state is behind ISIS, is bankrolling the caliphate. And truth be told, the reason ISIS wants to reign, and even more than just to reign population centers, it makes most of its money through taxation and a kind of petty bureaucracy.

WEISSYou know, oil is a factor, natural resources are certainly a factor and a main driver for their revenue. But when they take over a village, if it's a village of 700 people or, you know, 5,000, everyone in that village has to pay taxes. You have to put money into the kitty for -- to keep the caliphate afloat. This is the reason they have a geographical mission underlying their messianic ideology. So with respect to, you know, foreign operations, the way I've heard it described, and I think this is plausible, they wield a very light tough in terms of when they dispatch their agents into Europe or wherever.

WEISSThey give them the money to perpetrate attacks, but those guys are then tasked with doing logistics and target-scouting and essentially conceptualizing the exact nature of the terrorist attack themselves. But ISIS, again, this is a self-financed juggernaut. There is -- I mean, you have some charities and private sponsors in the Gulf who are giving nominal donations to ISIS via whatever sinuous means and methods. But, I mean, some of the reporting recently suggest that even U.S. financial institutions are essentially unwittingly laundering ISIS money through Iraqi banks, that ISIS is doing all kinds of, you know, under-the-table deals with money lenders and cash exchange offices in Iraq.

REHMBut you know, Michael, you've said that -- you've just said that ISIS dispatches these individuals where they want them to go and perpetrate these attacks. But at the same time, I'm understanding that many of these ISIS terrorists are actually homegrown in Europe. So which is it?

WEISSWell yes, but the people who are the -- I mean, we have so many different terms for this, ringleader, mastermind, you know, coordinator, the people who are essentially responsible for Paris and Brussels, they may have come from Europe, but they spent time in Syria. They were trained up in Al-Raqqah or Aleppo.

GERGESNot all of them, not, no, very few, very few.

WEISSNo, the Paris attackers, eight of the 10 attackers were...

GERGESVery few.

WEISSEight of the 10 attackers were featured...

GERGESThe evidence, the evidence that we have, Michael, is that...

REHMHold on, Fawaz, hold on one second. Go ahead, Michael.

WEISSEight of the 10 attackers after Paris were exhibited in an ISIS propaganda video on the battlefield, cutting people's heads off, and they were given short biographies. Their kunya or nom de guerre was put out there. They are then dispatched into Europe, and it is true, you don't have to have gone over to the caliphate, but these guys who will be the ones overseeing the networks, doing the recruitment, finding fellow travelers and affiliates and people who they can then rely on as either bagmen or logistics agents. I mean, the fact...

REHMAll right, now let's let Fawaz come in.

GERGESNo, no, I mean, I think -- I mean, there are ISIS, some fighters have returned to France, to Belgium, to Germany, to Britain, where I am. There is no doubt about it. But I'm afraid -- I was afraid that the way Michael has basically put it somehow that ISIS is basically -- has sent scores of fighters to establish bases all over Europe. You have certain individuals, certain fighters who have returned, but most of the militants, most of the radicalized religious activists, live in the heart of Europe. They have not gone -- they have not gone to Syria or to Iraq.

GERGESAnd this is really what worries, the lone wolves, the limited cells, and yes, having fought in Syria and Iraq makes a big difference operationally because they have the skills, they have the training, but the bomb maker in Belgium was not in Syria, did not go to Syria or Iraq, Najim Laachraoui. And other bomb makers, we know that they basically are radicalized either in their homes or in neighborhoods and what have you. And this is really what worries European security services the most, including the ones who basically have come back either from Syria or Iraq.

REHMAaron David Miller?

MILLERI think it's fair to say there's a deadly symbiosis between ISIS' direction and aspiration, between foreign fighters, commanders in the field and recruits in Europe who have never been to Iraq and Syria. I just have to add one additional point. This has been a thoroughly demoralizing and depressing conversation, and I think Fawaz's point of departure is correct. Even if the Europeans bring their counterterrorism culture and tactics into line, even if the Europeans find a better way to reintegrate a grieved, alienated Muslim community in Europe, the reality is that what Fawaz and Michael have alluded to is true.

MILLERYou have a broken, angry and dysfunctional Middle East, which will continue to provide fertile ground for years to come.

REHMAnd you're listening to the Diane Rehm Show. Are you saying that this struggle and these attacks are ongoing and endless?

MILLERI'm saying, Diane, that if you want Hollywood endings and happy endings when it comes to this.

REHMYou're not going to find it here.

MILLERYou should go to the movies. The reality is that you've got a Middle East in transformation, toward what we don't know, a lack of compelling individuals and leaders, a lack of compelling institutions, and as Fawaz and Michael have noted, a lack of compelling ideas to compete with the narratives.

REHMWhat do you believe the U.S. should be doing now? The New York Times has a lead editorial this morning saying America needs frank talk on ISIS. Seems to me we've talked a lot.

MILLERI'm not even sure what that means, nor as I listen to the Republican and Democratic debates do I detect ideas that are either new -- the ideas proposed by Republican and Democratic candidates either won't make a difference, are reckless, frankly, and/or are already being done. We just have to get real and understand that you're going to come up maybe with a proximate solution to what is not an insoluble problem. And until the Middle East house gets itself in order, perhaps with our help and that of the international community, this problem has no comprehensive solution.

REHMMichael, we're almost out of time. What in your mind should the U.S. be doing now?

WEISSI has to do more to convince Sunni Arabs that their plight and their suffering is in the American interest and that we are looking out for them. Right now Sunnis feel, even though they are the majority sect of Islam, as though they are a beleaguered and battered minority. ISIS is the only national security threat, but Iran and its manifold proxies and the Bashar al-Assad regime, which has killed more people than ISIS are left alone, if not are being seconded into a silent partnership with the West. That is a great source of alienation, a great source of grievance-making, and it is music to the ears of Abu Bakr al-Baghdadi because it's central to his narrative that the West cannot be relied on.

REHMAll right, and to you, Fawaz. What should the U.S. be doing now in very short period, please?

GERGESDiane, this is not about America. What's happening in the Middle East is not about America. America cannot and will not be able to resolve the structural problems of the Middle East. In fact I would argue as an American living outside America is it seems to me whenever we talk about the Middle East in America, we think somehow we have a magical wand.

GERGESThe U.S. has done enough damage. I really would like the Middle East to basically take care of its own problems, to basically take responsibility for its own challenges, to begin the process, basically, of rebuilding the state on new foundations. The most the United States can do is to help struggling societies to begin the process of institutional building, state-building, putting their productive bases and also keep a distance from the bloody dictators that have done a great deal of damage both to their own societies and also to global security, as well.

REHMAll right, we'll have to leave it there. Fawaz Gerges, his brand new book is titled "ISIS: A History," Michael Weiss of The Daily Beast is the author of "ISIS: Inside the Army of Terror," and Aaron David Miller is the author of "The End of Greatness: Why America Can't Have and Doesn't Want Another Great President." Thank you all so very much.

MILLERThank you, Diane.

WEISSThank you.

GERGESThank you.

REHMAnd thanks for listening, all. I'm Diane Rehm.