Khedery, the adviser to U.S. ambassadors, said Shiite Iran and the chief of Tehran's covert Quds Force, General Qassem Suleimani, played a central role in cementing other Shiite leaders' backing for Maliki. Iran pressured a key Shiite group loyal to firebrand cleric Muqtada al-Sadr, who had feuded with Maliki, to support him.
A year later, the last U.S. combat troops left Iraq, taking with them much of Washington's remaining clout in the country and leaving behind a flawed leader.
"Not only was this predictable, but it was predicted—it was preventable," Khedery said of Iraq's current catastrophe.
On December 15, 2011, then-U.S. Defense Secretary Leon Panetta watched as U.S. soldiers at Baghdad's heavily fortified airport lowered the flag of American forces in Iraq, marking the end of Washington's Iraq adventure.
"Challenges remain, but the United States will be there to stand by the Iraqi people," Panetta said at a modest ceremony notable for the absence of Iraq's most senior politicians, who portrayed the withdrawal as a victory for Iraqi sovereignty.
How closely the Obama administration stood by after 2011 to prevent the worsening of Iraq's sectarian divisions is open to debate.
Even as Panetta spoke, government forces had surrounded the home of Vice President Tariq al-Hashimi, Iraq's highest-ranking Sunni official, suspected by Maliki and other officials of ties to killings and bombings—links he has always denied. Four days later, Iraq's Interior Ministry issued an arrest warrant for Hashimi. He fled Baghdad for Iraqi Kurdistan and was later sentenced to death in absentia. The U.S. response was muted, partly because Obama administration officials believed allegations against Hashimi's entourage had merit and because not many Sunnis rushed to defend Hashimi, the officials said.
U.S. officials were more troubled by Maliki's move a year later against another of the country's top-ranking Sunnis, popular Finance Minister Rafi Issawi, for alleged ties to militants. In December 2012, government forces detained a number of Issawi's bodyguards, provoking protests in Anbar, Issawi's home province. Issawi resigned in March 2013.
"Issawi was a different story. There was a lot of concern about that. We made our concern well known," a U.S. official said on condition of anonymity. But the incident barely registered publicly in Washington, where the White House was focused on the worsening conflict in Syria.
The U.S. embassy saw Issawi, a former surgeon, as a moderate Sunni with whom they could do business. Sky said U.S. intelligence officials looked into accusations against Issawi and judged him innocent. In the Issawi case and others, U.S. diplomats sought to stop Maliki and other politicians from inflaming sectarian tensions, the official said. "We've prevented them from doing some things, but some things [we] haven't been able to," he said. "And I think that’s kind of what's led us to where we are today."