US President Barack Obama speaks on the phone with King Abdullah II of Jordan in the Oval Office of the White House on August 8, 2014 in Washington, DC
Washington (AFP) - He was elected on a promise to end America's "dumb war" in Iraq.
Now, in launching US air strikes to counter a "barbaric" offensive by jihadist militants, a reluctant Barack Obama has reopened a chapter of recent American history he had once dared hope was finished.
In 2012, he was proud to run for re-election as the man who a year previously had finally withdrawn US troops from a "stable, sovereign Iraq," eight long years after his predecessor had sent them in.
Now he becomes the fourth US president in a row to take military action there, after George Bush drove Iraqi troops from Kuwait, Bill Clinton bombed its air defenses and George W. Bush invaded.
On Thursday, Obama outlined his reasons for what he hopes will be a limited engagement: Extremist insurgents were massacring Yazidi and Christian refugees and threatening to march on Arbil.
The northern city is the capital of Iraq's autonomous Kurdish region, one of the few reliably pro-American parts of the country, and base to a large number of US advisers and officials.
Obama said he could not stand by if Iraq's religious minorities are slaughtered by Sunni Muslim extremists, nor if American personnel are at risk, but insisted this was not the start of a new conflict.
"As commander-in-chief, I will not allow the United States to be dragged into fighting another war in Iraq," he insisted. "American combat troops will not be returning to fight in Iraq."
But, as many recent conflicts have shown, and as Obama must know full well, once US jets were in the air and strikes had begun, it was impossible to know for sure where the conflict would lead.
"The pressure will always increase for the US to do more because they have already admitted that there is a problem there," said Julian Zelizer, Princeton University professor of history and public affairs.
"At this point, we don't know but it is clearly foreseeable that his promise that this will be limited won't hold true."
The White House's definition of the mission -- feed and protect besieged refugees, protect Arbil and US lives -- leaves enough leeway for commanders to take wide-ranging action.
The first strike confirmed Friday by the Pentagon targeted an artillery piece that Islamic State insurgents had turned on Kurdish forces defending Arbil "where US personnel are located."
But defending Arbil will not destroy the so-called Islamic State, which now rampages across much of northern Iraq and eastern Syria on a bloody quest to establish an Islamic caliphate.
Obama's enemies in Washington are demanding tougher action.
"We need to get beyond a policy of half-measures," declared Republican hawks John McCain and Lindsey Graham in a joint statement released after Obama announced military action.
"We need a strategic approach, not just a humanitarian one," they said, calling for air strikes on IS forces, bases and leaders in both Iraq and Syria, and arms shipments to the group's local opponents.
"If ever there were a time to reevaluate our disastrous policy in the Middle East, this is it," McCain and Graham declared.
"Because of the president's hands-off approach, the threats in the region have grown and now directly threaten the United States."
- Regrets over US withdrawal -
Obama's critics see the chaos in Iraq as the logical conclusion to his failure to insist on a continued US military presence in Iraq after 2011 -- despite the opposition of the Baghdad government.
US troops, they feel, could have stiffened the resolve of Iraqi forces and dissuaded Prime Minister Nuri al-Maliki's Shiite-led government from alienating Sunni tribes that once fought Al-Qaeda.
Washington hardliners like McCain have also pushed for the United States to arm "moderate" rebel factions in Syria, in order to prevent extreme groups like the Islamic State from dominating the battlefield.
Obama's White House disputes these arguments, saying that a residual US presence -- even if Maliki had agreed to host it under reasonable terms -- would not have held back the jihadist tide.
"The argument that those individuals are making is that the situation might be different if there were still tens of thousands of American troops in a combat role in Iraq," said Obama spokesman Josh Earnest.
"The consequence of that sort of military posture is that right now American servicemen and women would be on the front lines fighting ISIL in cities and towns all across Iraq."
And the administration can point to a wealth of polling data showing that Americans are loathe to be dragged into yet more wars in the Muslim world, 13 years after the September 11 attacks.
Nevertheless, with images arriving of Christian villages emptied and Yazidi families starving exposed on a mountainside, Obama felt he had to sell his people on at least one more mission.
"I know that many of you are rightly concerned about any American military action in Iraq, even limited strikes like these," he said.
"But when the lives of American citizens are at risk, we will take action," he added. "And when many thousands of innocent civilians are faced with the danger of being wiped out... we will take action.
"That is our responsibility as Americans. That's a hallmark of American leadership. That's who we are," his words determined, even if his grim demeanor betrayed a reluctance to roll the dice.
Zelizer summed up the view of other observers watching Obama's performance: "He is going in this hesitantly, people read it that way, and he has not done a very good job hiding it."