Back around 2008, al-Qaeda in Iraq (AQI) had been decimated. Its founder (Abu Musab al Zarqawi) was dead, along with many of his lieutenants, and it had lost the support of the Sunni community. Consequently, American and Iraq forces, working with the Sons of Iraq militia, were able to rout the terrorist group out of its lairs and break its hold on a swath of territory the size of New England.

That was then, this is now.

On Monday, at the start of Ramadan, Iraq experienced the bloodiest day of the year, with more than 100 people killed and 300 wounded in a series of at least 40 separate attacks around the country. Some of the attacks were carried out with car bombs, others with direct assaults on security personnel. Claiming responsibility was none other than AQI, whose shadowy leader, Abu Bakir al Baghdadi, claimed this was part of a new offensive called Breaking Down Walls.

So much for the claims of American and Iraqi officials that violence is on the wane. In fact, as noted by the New York Times, “The attacks were likely to continue the trend of the first six months since the departure of American troops, when violence has steadily increased, according to United Nations statistics.” If the trend continues this will mark a remarkable defeat–and a self-inflicted one–for American policy in the Middle East.

If only the U.S. had been able to keep troops in Iraq past 2011, the odds are that Iraqi forces would have had greater success in continuing to crack down on AQI. The U.S. presence was particularly important for providing intelligence support to the Iraqis as well as pressuring Prime Minister Maliki to share power with Sunnis so as to avoid fueling a sectarian conflagration. With the U.S. out of the picture, Maliki is busy accumulating dictatorial power and the Iraqi security forces appear to be fighting half-blind, thus allowing AQI to rise from the grave like a zombie.

It did not have to be this way. Although there is no way to prove a counterfactual, I am convinced the U.S. could have won Iraqi political support to maintain a troop presence past 2011 if President Obama had gone all-out to push for it. But he didn’t, preferring to suspend negotiations at the first stumbling block (over immunity for U.S. troops). The result is a tragedy for Iraq–and a possibly grave defeat for the United States.