Couriter-ISIL campaign tops $3 billion.

• Author: Harper, Jon
• Position: Budget Matters

* A year into the conflict, U.S. military operations against the Islamic State in Iraq and Syria have cost the Defense Department more than $3.2 billion, according to the Pentagon.

The bulk of the cost has been borne by the Air Force, which is leading the bombing campaign against the militants. The service has spent more than $2.1 billion on the air war, including munitions and mission support functions. The Navy, which has been launching strike and reconnaissance platforms from aircraft carriers in the Persian Gulf, has spent about $500 million. The war effort has cost the Army and U.S. Special Operations Command approximately $350 million and $250 million, respectively.

The U.S. began bombing Islamic State targets in Iraq in August 2014, and the effort expanded to Syria the following month. U.S. Central Command has launched more than 5,000 airstrikes against the militants and destroyed more than 7,000 enemy targets, including tanks, Humvees, buildings, oil infrastructure, staging areas and fighting positions, U.S. officials said. In addition, approximately 3,500 American troops are in Iraq performing a train, advise and assist mission.

Although anti-Islamic State forces on the ground--backed by U.S. airpower--have pushed the jihadists out of places like the Iraqi city of Tikrit and the Syrian town of Kobane, the group continues to hold key terrain and remains a potent adversary, U.S. officials and defense experts have noted.

Christopher Harmer, a defense analyst at the Institute for the Study of War, described the air campaign as "tactically spectacular" but having limited "strategic impact" because the group still controls major areas and population centers, maintains the ability to launch offensive operations, and is able to communicate with and recruit foreign fighters and sympathizers.

Some observers have criticized the restrictions that President Barack Obama has placed on the U.S. military effort, including prohibiting special operators from joining the front lines to...