US military action against Islamic State militants in Iraq and Syria began on a small scale three months ago but has steadily expanded in size and scope, raising the stakes for Washington, experts say.
The mission has morphed from protecting religious minorities in Iraq to a vow to “destroy” the IS group in both Syria and Iraq, a dramatic shift for an American president who as a candidate was an outspoken opponent of the previous US war in Iraq.
“As commander in chief, I will not allow the United States to be dragged into another war in Iraq,” President Barack Obama said on August 7, when he announced the first US air strikes against the IS group in Iraq.
But last week, Obama approved reinforcements that will bring the total military footprint to 3,100 troops in Iraq, with a new mission to shape the government army into an effective fighting force.
The justification for the initial US bombing raids in August was narrowly defined — to protect US diplomats in northern Arbil and to prevent a massacre of besieged Yazidis on Mount Sinjar.
After more than 800 air strikes, there is no end in sight and US officials say the fight could last years.
The step-by-step expansion of the war effort is a familiar pattern for American presidents, and Congress tends to give the commander-in-chief a green light, Zenko said.
“Every administration does this. It´s not unique to this White House,” he added.