Coalition strikes on high-value ISIS targets have killed 70 senior and mid-level leaders since May, a rate of one leader killed every two days, the spokesman for the US-led coalition said. The coalition estimates that between 20-30,000 ISIS fighters remain on the battlefield, but aircraft have been able to kill replacement fighters as fast as they have been recruited, Army Col. Steve Warren, spokesman for Combined Joint Task Force-Operation Inherent Resolve, said Oct. 13. “We’re drying up their bench by killing this many of their leaders, they’re having to go to second- and third-tier leaders.” The coalition estimate of ISIS’s end strength, however, shows the group is able to fulfill its ranks despite constant airstrikes. The numbers are identical to an intelligence estimate of the group from July 2014, according to a report earlier this year in USA Today.
While some of the Air Force's newly announced changes will happen quickly, it may take most of Chief of Staff Gen. David W. Allvin's tenure in the job to accomplish the rest, he said in a Brookings Institution event Feb. 28.