Is the United States killing enough Islamic State in Iraq and Syria (ISIS) militants?
It may be a macabre question but it is also a necessary one, according to some defense experts. They wonder whether the military efforts by the U.S.-led coalition, especially those centered on the Syrian border town of Kobani, are inflicting enough damage to counter-balance an influx of ISIS fighters into the area.
The U.S.-led coalition has dropped nearly 500 warheads in and around Kobani over the past three weeks, according to Defense officials.
A defense official who did not want to be identified said Wednesday that the number killed was in excess of 350.
As many as 9,000 ISIS fighters have streamed to the town to take on 3,000 Kurdish fighters who are seeking to repel the ISIS advance.
Defense officials have suggested that the number of ISIS fighters killed is not the only metric of progress, or even the primary one.
"The effort there isn't just about warheads on foreheads,” Kirby said Wednesday. "I'm not diminishing the importance of taking fighters off the battlefield. But that's not ... the overarching goal here.”
But at the same time, Pentagon officials say they are in fact trying to kill as many ISIS members as they can in Kobani.
"We've used the tried-and-true method of 'Kill them where they are,'" said Pentagon spokesman Army Col. Steve Warren on Wednesday.
Last week, Army Gen. Lloyd Austin, commander of the military campaign against ISIS, said U.S. airstrikes in and around Kobani were meant to degrade ISIS’s strength overall.
"The more we attrit [the enemy] in Kobani, the less ability he has to reinforce efforts ... in other places," he said on Friday.
But Defense officials also say ISIS can be degraded by taking out heavy weapons, vehicles and oil refineries controlled by the militant group.
The administration also emphasizes that it’s important to defeat ISIS’s ideology, which replenishes the group with new recruits — and which, by its nature, cannot be vanquished by military force.
Outside experts agree that the number of ‘kills’ is not the be-all and end-all of military success. But many say the numbers do matter.
“They matter because the numbers have an impact on whether or not you’re going to succeed in accomplishing a particular military objective,” said retired Air Force Lt. Gen. David Deptula.
“If you reduce the number of adversary forces…it assists the Kurdish folks who are fighting to maintain that town,” he added.
Officials have refrained from giving out enemy casualty numbers for the overall fight against ISIS, though the CIA estimates ISIS's overall strength at between 20,000 and 30,000 people.
But the casualty numbers in Kobani provide a peek at the damage being done in an area that has become an early litmus test of the U.S. strategy against ISIS, which relies on airstrikes and indigenous ground forces.
So far, the U.S.-led coalition has devoted roughly half of its 300 airstrikes in Syria over the last few weeks to the area in and around Kobani. But ISIS’s advances have only recently — and perhaps just temporarily — been halted. Defense officials say the situation is fluid and contested.
Deptula, who planned the air war in Operation Desert Storm and was the director of the Combined Air Operations Center for the 2001 invasion of Afghanistan, said there should be hundreds of airstrikes against ISIS per day.
“The average number of strike sorties per day since we started this operation [has] been seven,” he said. “Imagine if those numbers were doubled or tripled.”
Michael Knights, research fellow at the Washington Institute for Near East Policy, agreed.
“The amount of force we’re using right now is minuscule compared to what we could use. So as a result, it is going to be slow, because the U.S. has decided upon a low-risk and low-reward approach to the Syrian crisis and to the Iraq crisis,” he said.
Defense officials have urged the American public to be patient with respect to a military effort that has so far cost $424 million since Aug. 8, and is proceeding at a cost of $7.6 million per day.
Knights, who has worked extensively in Iraq as a consultant, said the slow pace was limited not by any lack of resources, but the lack of intelligence for more airstrikes.
“The problem is the bottleneck of, ‘Are we sure that thing I’m looking at is what I think it is? Am I sure that it is an ISIS technical [vehicle] ... or could it be a bunch of civilian people with a rug on the back of a truck?’
Kirby acknowledged those limits on Wednesday.
“There’s going to be a limit, though. You can't just hit every place you know them to be, because ... unlike them, we have to be discreet and [discriminating] about collateral damage and civilian casualties,” Kirby said.
“We need that acuity, and that’s the short pole in the tent, where you don’t have the intelligence assets in place. But if we had them in place, sure, we could absolutely clean these guys’ clocks,” he said.
This story was updated at 12:57 p.m.