For years, Americans have made one thing very clear: They want no part of overseas conflicts.

In Iraq, that long-standing aversion is being put to the test.

President Obama’s authorization late Thursday for airstrikes and humanitarian aid in Iraq will undoubtedly bring back a host of emotions for Americans, whose forces withdrew from that same country less than three years ago.

Americans have so far been deeply ambivalent toward further military action in Iraq. A June Washington Post-ABC News poll found fewer than half, 45 percent, supported launching airstrikes against Sunni extremists in the country, and only 30 percent supported deploying ground troops. Separate surveys found majorities believing the U.S. does not have a responsibility to stop violence in the country.

Washington Post-ABC News poll June 18-22 among random sample of 1,009 adults. Error margin 3.5 percentage points.

Public opinion surveys find that, in general, Americans say they overwhelmingly support military action to prevent genocide or retaliate against the use of chemical weapons. But support has been far lower when it comes to specific conflicts in which such things might be involved. Iraq presents just such a difficult choice.

Obama acknowledged the public’s skepticism directly in a statement Thursday evening, counseling “I know that many of you are rightly concerned about any American military action in Iraq — even limited strikes like these. I understand that.” But the plight of a starving and endangered religious minority known as the Yazidi demanded U.S. action, Obama argued. “They’re without food, they’re without water. People are starving. And children are dying of thirst. Meanwhile, ISIL forces below have called for the systematic destruction of the entire Yazidi people, which would constitute genocide."

Prevention of genocide and starvation is among the most potent arguments Obama could make for getting involved in Iraq. When a 2012 survey by the Chicago Council on Global Affairs asked Americans under what circumstances they would favor deploying U.S. troops, stopping a government from killing its own citizens topped the list with 70 percent in favor. In Iraq, Sunni extremist groups — not the government — are responsible for the killings, but the prevention of certain death is a great motivating factor nonetheless.

The next most popular reason for using force in the survey was dealing with a humanitarian crisis, which 66 percent favored. Both genocide and humanitarian intervention were far more acceptable rationales for force than intervening if U.S. allies such as Israel, South Korea or Taiwan were invaded by their neighbors.

But the public’s overwhelming support for action to stop genocide in principle has not always translated to support for specific military interventions. More than six in 10 Americans opposed launching airstrikes in Syria in a Post-ABC poll last September, even after the Obama administration and other nations claimed that Syria’s government had used chemical weapons on its own people during the nation’s civil war.

Support for Obama’s intervention in Iraq is unclear, but skepticism could be heightened given the overall unpopularity of America’s nine-year war in which 4,425 American service members died. Well-forged skepticism about the utility (or futility) of U.S. actions may limit the public’s willingness to support additional actions sought by the Obama administration.

But there also might be an interesting political twist to Obama’s decision to order airstrikes in Iraq. Obama has weathered middling approval ratings for his handling of international affairs this summer. When the ISIL threat emerged earlier in June, the public divided 45 percent in support to 46 percent in opposition to the idea of using missiles against the Sunni insurgents.

But what was the one group that offered majority support for such airstrikes? Republicans. Nearly six in 10 Republicans (58 percent) supported it, compared with 45 percent among Democrats and 41 percent among independents.

Initial reaction from Republican senators on the Foreign Relations committee has been mixed. John McCain (R.-Ariz.) and Lindsey Graham (R.-S.C.) said it was the right thing for Obama “to provide humanitarian relief to the Iraqi civilians” as well as authorizing military strikes. But the statement from the senators also said the actions haven’t gone far enough and that a “strategic approach” to the situation is warranted, and “not just a humanitarian one.”

It remains to be seen whether Obama’s base will get behind this decision or if Republicans will follow through with supporting any action by the president.

But after a long succession of hypotheticals when it comes to American military action overseas, we're finally going to see how Americans view real action.