On Aug. 8, 2014, the U.S. began bombing the Islamic State around Sinjar in northern Iraq, beginning what has become a larger U.S.-led air campaign against ISIS in Iraq and Syria. In the two years since, the U.S. has conducted more than 9,400 strikes on ISIS in Iraq and another 4,700 in Syria (while 12 coalition countries have hit ISIS with 3,018 strikes in Iraq and 249 in Syria). These anti-ISIS airstrikes have cost the U.S. $11.9 million a day, or $8.4 billion as of July 15, and three U.S. service members have been killed in combat in Iraq and Syria. The U.S. says since Operation Inherent Resolve began two years ago, ISIS has lost more than 40 percent of its territory in Iraq and Syria.
When announcing the operation, President Obama said that he will "not allow the United States to be dragged into fighting another war in Iraq," and "American combat troops will not be returning to fight in Iraq." That has meant an air war, supporting the Iraqi army and various militias, most notably the Kurdish peshmerga and YPG forces, though the U.S. has about 3,800 military personnel stationed in Iraq, plus hundreds more on temporary duty, according to the Pentagon. The use of U.S. air power has been a major driver in ISIS's losses, but as The Associated Press notes, the airstrikes have "also leveled entire neighborhoods," leaving "in many cases... a ruined prize." You can learn more about what Iraq has gained and ISIS has lost over the past two years at AP and the Defense Department.