Things are going from bad to worse in the Middle East:

But for all its echoes, the bloodshed that has engulfed Iraq, Lebanon and Syria in the past two weeks exposes something new and destabilizing: the emergence of a post-American Middle East in which no broker has the power, or the will, to contain the region’s sectarian hatreds.

Amid this vacuum, fanatical Islamists have flourished in both Iraq and Syria under the banner of Al Qaeda, as the two countries’ conflicts amplify each other and foster ever-deeper radicalism. Behind much of it is the bitter rivalry of two great oil powers, Iran and Saudi Arabia, whose rulers — claiming to represent Shiite and Sunni Islam, respectively — cynically deploy a sectarian agenda that makes almost any sort of accommodation a heresy.

“I think we are witnessing a turning point, and it could be one of the worst in all our history,” said Elias Khoury, a Lebanese novelist and critic who lived through his own country’s 15-year civil war. “The West is not there, and we are in the hands of two regional powers, the Saudis and Iranians, each of which is fanatical in its own way. I don’t see how they can reach any entente, any rational solution.”

The drumbeat of violence in recent weeks threatens to bring back the worst of the Iraqi civil war that the United States touched off with an invasion and then spent billions of dollars and thousands of soldiers’ lives to overcome.

Al Qaeda now runs Fallujah, a city US forces pacified in 2004 at the cost of 90 US Marine lives, and hundreds of serious US casualties. McCain and Graham are saying, “I told you so,” but it is impossible to believe that a perpetual American occupation of Iraq was militarily or politically sustainable. Obama did the best he could with the terrible hand he was dealt.

That said, watching what’s happening in the Middle East today, and how well our nation-building has gone in Iraq and Afghanistan, one can only be grateful that renegade Republicans and Democrats, backed by the American public, stayed the president’s hand against Syria last year.