The challenge posed to the Middle East, and ultimately to America, by the group calling itself the Islamic State (also known as ISIS or ISIL) has unleashed a U.S. debate of profound implications for the country’s policy making. Reduced to its essence, it can be articulated with this question: Who is more responsible for the rise of ISIS, George W. Bush or Barack Obama?

Those who pin the blame on Obama offer an argument that goes something like this: When Bush left office, he left behind an Iraqi state that was functioning and stable, thanks largely to the president’s 2007 “surge” of troops that ended a Sunni insurgency threatening to tear the country apart. All that was needed was for Obama to leave a residual U.S. military force in the country to maintain internal stability and counter any threat that might arise from Islamist radicals.

But (continuing the blame-Obama argument) the new president never appreciated the crucial importance of resolve and force in preserving global peace, for he believed that a large portion of global anti-Americanism stemmed from overly aggressive actions on the part of the United States. As the Wall Street Journal put it in a recent editorial:

“Recall that Mr. Obama won the Presidency by arguing that the U.S. had alienated the world and Muslims by recklessly using force abroad. We had betrayed our values by interrogating terrorists too harshly and wiretapping too much. Our enemies hated us not because they hated our values or our influence but because we had provoked them with our interventions.”

And so, added the Journal, Obama withdrew from the Middle East, particularly from Iraq, and avoided new entanglements, such as in Syria after its leader, Bashar al-Assad, came under attack from a powerful insurgency. It suggested also that the president has offered only weak responses to the ongoing aggressiveness of Russia, Iran and other U.S. adversaries in hopes that “the anti-American furies would subside and the world would be safer.”

In the view of those who see Obama as primarily responsible for the rise of ISIS, the original Bush strategy had been sound and was working until Obama’s full military withdrawal from Iraq opened up an avenue for the ISIS invasion. And that invasion was launched from ISIS’ foothold in Syria only after Obama had paved the way for its rise there by refusing to support moderate anti-Assad forces, which could have blunted the rise of ISIS, even as they fought Assad. The Journal summed up this historical view with a provocative flourish: “One way to start undoing the damage would be to concede that Dick Cheney was right all along.”

Like most elaborate public-policy arguments, this one contains a certain amount of truth. Obama did subordinate the significance of force to a more wispy notion of seeking stability in troubled regions through “soft-power” policies designed to assuage anti-American sentiments. And it’s possible that he could have negotiated a “status of forces” agreement with Iraq that could have made possible an ongoing U.S. residual force in that country. The lack of such a force no doubt contributed to the ISIS emergence. As National Interest publisher Dimitri K. Simes has written in these spaces, America’s complete withdrawal allowed former prime minister Nouri al-Maliki to act on his deeply divisive authoritarian and sectarian impulses, which in turn created the ISIS opportunity in Iraq.

Further, those who argue that Obama’s foreign policy has been disjointed, ad hoc and largely ineffectual cannot be easily dismissed.

But any robust understanding of the ominous rise of ISIS must circle back to the tragic actions of George W. Bush, who lost his way almost immediately after the 9/11 attacks that killed nearly 3,000 Americans as they went about their daily routines in their own land. The powerful events of that fateful day demonstrated that America had a new enemy that needed to be understood fully. The enemy was Islamist radicalism, a substantial body of sentiment within the broader world of Islam.

Bush quickly concluded that Islamist radicalism was a warped and alien impulse within Islam that could be countered by demonstrating to mainstream Muslims the virtues and joys of Western democratic institutions. This was his first mistake. Islamist radicalism is a natural outgrowth of fundamental Islamic sentiments that have contributed to centuries of hostility between the West and Islam. As the late Harvard political scientist Samuel P. Huntington has written, “Some Westerners…have argued that the West does not have a problem with Islam but only with violent Islamist extremists. Fourteen hundred years of history demonstrate otherwise….Across the centuries the fortunes of the two religions have risen and fallen in a sequence of momentous surges, pauses, and countersurges.”

Given this civilizational tension going back centuries, two imperatives confronted any president seeking to protect Americans from Islamist radicalism. First, America must refrain from actions that could unnecessarily inflame the world of Islam, including actions that could unleash anti-American fervor and also actions that could stir sectarian strife in regions where sectarian tensions have always been just beneath the surface of society. Second, it must enlist forces within Islam that were themselves hostile to Islamist radicalism and could assist in the effort to keep it under control. Some of the most powerful of these forces included the largely sectarian governmental dictatorships of Egypt, Syria, Libya and, yes, Iraq.

Bush ignored both of these imperatives when he invaded Iraq, and the fallout belongs to him. The invasion unleashed profound sectarian strife when minority Sunnis, who had dominated the region for centuries, suddenly found themselves vulnerable to vindictive Shiite leaders installed by America. Many Sunnis aligned themselves with Al Qaeda elements that flooded the country, bent on exploiting this chaos to establish a safe haven for themselves. Bush’s 2007 “surge,” far from any kind of successful military action, actually was a kind of cover for diplomatic efforts to get traditional Sunni leaders to turn on their erstwhile Al Qaeda collaborators. They did so under assurances that the new government under Nouri al-Maliki, a Shiite, would protect Sunni interests and safety.

That Maliki ultimately would seek to assault Sunni interests was entirely predictable (particularly after the full U.S. withdrawal), and it further ensured ongoing chaos in Iraq (which aided ISIS’ Iraq invasion years later). Also predictable was Maliki’s alignment with Iran, a U.S. adversary, which upended a regional balance of power that had been very much in America’s interest for decades. Meanwhile, the planting of the U.S. flag upon the heartland soil of Islam inflamed anti-American passions throughout the region, which were intensified by the idea, inherent in the Bush policy, that America would remake the lands of Islam in the image of Western pluralistic democracy.

In light of all this, it would have been difficult for any residual American military force in Iraq to stem the tide of instability and radicalism that engulfed the country, particularly after so many elements of stability in the region had been upended in the so-called Arab Spring, encouraged and fostered by Obama in keeping with the same philosophy that had guided Bush into the region. Obama also followed the Bush philosophy in declaring early in the Syrian bloodshed that Assad must go. As Simes wrote, this “gave a false encouragement to the opposition and contributed to the country’s [eventual] bloody civil war,” as well as the decision of neighboring states, particularly Turkey, to support the insurgency and thus discourage any kind of negotiated outcome.

Thus, while Obama’s policies lacked any serious degree of strategic coherence, some of his biggest mistakes resulted from his embrace of the Bush outlook that originated the current unwieldy chaos in the region.

In any event, in answer to the Journal’s suggestion that we should acknowledge Dick Cheney’s wisdom from the beginning, it can be said:

Cheney was wrong to support the invasion of Iraq in 2003. He was irresponsibly wrong when he assured the nation, without serious evidence, that Iraq’s Saddam Hussein possessed weapons of mass destruction. He was wrong to argue that Saddam was in alignment with Al Qaeda leaders. He was wrong when he assured the American people that U.S. forces would be greeted as liberators rather than invaders. He was wrong to think that Western-style democracy could be planted upon the soil of a culture that contains doctrinal objections to significant elements of Western-style democracy. He was wrong to miss the implications of destroying the balance of power between Iraq and Iran. He was wrong not to see the consequences of the ongoing societal chaos in Iraq that would be unleashed by the invasion.

As for Obama, his most serious lapses resulted from his embrace of the outlook that guided his predecessor into Iraq in the first place—the idea that democracy could sprout in Islamic soil in the wake of the Arab Spring; the notion that American interests could be served by helping upend Libya’s Muammar Qaddafi; the idea that the country could benefit by setting itself against other secular leaders in the Middle East, including Assad; the concept that a modest American force could change Afghan tribal practices that have been in force for centuries. His only serious gaffe that wasn’t in keeping with the Bush outlook was his complete military withdrawal from Iraq.