Given American military might and the belief that democracy was sweeping the globe, the Bush administration and its supporters reasoned that it would be relatively easy to remake the Arab and Muslim world in America’s image. They were wrong, of course, for the Bush administration failed to understand the limits of what American military power could do to transform the Middle East.

THE FAULTY assumption that America could perform social engineering through its indomitable military might—beyond the lofty theorizing of the neoconservatives—found its roots in Afghanistan. By December 2001, it appeared that the U.S. military had won a quick and stunning victory against the Taliban and installed a friendly regime in Kabul that would be able to govern the country effectively for the foreseeable future. Very importantly, the war was won with a combination of American airpower, local allies and small Special Forces units. How easy it seemed to deliver that country its freedom. There was no need for a large-scale invasion, so when the fighting ended, the United States did not look like an occupier. Nor did it seem likely to become one, because Hamid Karzai was expected to keep order in Afghanistan without much U.S. help.

The perception of a stunning triumph in Afghanistan was significant because leaders rarely initiate wars unless they think that they can win quick and decisive victories. The prospect of fighting a protracted conflict makes policy makers gun-shy, not just because the costs are invariably high, but also because it is hard to tell how long wars will come to an end. But by early 2002, it seemed that the United States had found a blueprint for winning wars in the developing world quickly and decisively, thus eliminating the need for a protracted occupation. It appeared that the American military could exit a country soon after toppling its regime and installing a new leader, and move on to the next target. It looked like the neoconservatives had been vindicated. This interpretation convinced many people in the foreign-policy establishment that the road was now open for using the U.S. military to transform the Middle East and dominate the globe.

And with this hubris firmly in place, America attacked Iraq on March 19, 2003. Within a few months, it looked like the “Afghan model” had proved its worth again. Saddam was in hiding and President Bush landed on the USS Abraham Lincoln with a big banner in the background that announced: “Mission Accomplished.” It seemed at the time that it would not be long before the next war began, maybe against Iran or Syria, and then the other states in the region might be so scared of America that merely threatening them with an attack would be enough to cause regime change.

It all turned out to be a mirage, of course, as Iraq quickly became a deadly quagmire with Afghanistan following suit a few years later.

Indeed, what initially appeared to be a dazzling victory in Afghanistan was not. There was little chance that the United States would avoid a protracted occupation, since we faced two insurmountable problems. While it was relatively easy to topple the Taliban from power, it was not possible for the American military and its allies to decisively defeat that foe. When cornered and facing imminent destruction, Taliban fighters melted away into the countryside or across the border into Pakistan, where they could regroup and eventually come back to fight another day. This is why insurgencies with external sanctuaries have been especially difficult to stamp out in the past.

Furthermore, the Karzai government was doomed to fail, not just because its leader was put in power by Washington, and not just because Afghanistan has always had a weak central government, but also because Karzai and his associates are incompetent and corrupt. This meant that there would be no central authority to govern the country and check the Taliban when it came back to life. And that meant the United States would have to do the heavy lifting. American troops would have to occupy the country and fight the Taliban, and they would have to do so in support of a fragile government with little legitimacy outside of Kabul. As anyone familiar with the Vietnam War knows, this is a prescription for defeat.

If more evidence is needed that the “Afghan model” does not work as advertised, Iraq provides it. Contrary to what the neoconservatives claimed before the invasion, the United States could not topple Saddam and avoid a long occupation, unless it was willing to put another dictator in charge. Not only did Baghdad have few well-established political institutions and a weak civil society, the removal of Saddam was certain to unleash powerful centrifugal forces that would lead to a bloody civil war in the absence of a large American presence. In particular, the politically strong Sunnis were sure to resist losing power to the more numerous Shia, who would benefit the most from the U.S. invasion. There were also profound differences among various Shia groups, and the Kurds did not even want to be ruled by Baghdad. On top of all that, al-Qaeda in Mesopotamia eventually emerged on the scene. (Of course, the United States did not face a terrorist threat from Iraq before the invasion.) All of this meant that a protracted American occupation would be necessary to keep the country from tearing itself apart.

AND LONG, messy occupations were always inevitable. For though one might argue that the United States would have succeeded in Afghanistan had it not invaded Iraq and instead concentrated on building a competent government in Kabul that could keep the Taliban at bay, even if this were true (and I have my doubts), it still would have taken a decade or more to do the job. During this time the U.S. military would have been pinned down in Afghanistan and thus unavailable to invade Iraq and other countries in the Middle East. The Bush Doctrine, however, was dependent on winning quick and decisive victories, which means that even a drawn-out success in Afghanistan would have doomed the strategy.

Alternatively, one might argue that the main problem in Afghanistan and Iraq was that the U.S. military had a flawed counterinsurgency doctrine during the early stages of those conflicts. According to this story, the United States eventually found the right formula with the December 2006 edition of the U.S. Army and Marine Corps Counterinsurgency Field Manual 3-24 (FM 3-24). Indeed, the purported success of the Iraq surge is often ascribed to the implementation of the new rules of engagement. Some even claim that it has helped us achieve victory in Iraq. The problem with this argument is that President Bush made clear when the surge was launched in January 2007 that tamping down the violence was a necessary but not sufficient condition for success. He wisely emphasized that it was also essential that rival Iraqi groups ameliorate their differences and find a workable system for sharing political power. But to this day there has been little progress in fixing Iraq’s fractured society and building an effective political system, as evidenced by the difficulty Iraqi politicians have had forming a government in the wake of the March 7, 2010, parliamentary elections. Hence, the surge has not been a success. This failure is not for lack of trying; nation building is a daunting task. The scope of the challenge is still greater in Afghanistan. So even if one believes that the American military now has a smart counterinsurgency doctrine, the fact is that it has yet to succeed.

There is no question that it is possible to defeat an insurgency, but it is almost never quick or easy, and there is no single formula for success. As FM 3-24 warns, “Political and military leaders and planners should never underestimate its scale and complexity.” Even in a best-case scenario like the Malayan Emergency, where the British faced a numerically weak and unpopular Communist guerrilla force based in the small Chinese minority, pacification still took roughly a dozen years. What makes the enterprise so difficult is that victory usually requires more than just defeating the insurgents in firefights. It usually demands nation building as well because it is essential to fix the political and social problems that caused the insurgency in the first place; otherwise, it is likely to spring back to life. So even if it was a sure bet that the United States could succeed at counterinsurgency with the right people and doctrine, it would still take many years to achieve decisive results. “Insurgencies,” as FM 3-24 notes, “are protracted by nature.” This means that when the American military engages in this kind of war fighting, it will end up pinned down in a lengthy occupation. And when that happens, the Bush Doctrine cannot work.

BUT THE Bush administration and its neoconservative supporters badly miscalculated how easy it would be to create free, stable societies in the Middle East. They thought that beheading regimes was essentially all that was needed for democracy to take hold.