Success in the effort to degrade, defeat and destroy the Islamic State of Iraq and the Levant shouldn’t be considered simply in terms of a body count or how much land has changed hands, Pentagon Press Secretary Navy Rear Adm. John Kirby said today.

“What makes these guys different than a group like al-Qaida is they do have territorial designs. They have governing ambitions,” Kirby told reporters during a regular Pentagon news briefing.

“They talk about this caliphate vision of theirs. And in order to govern, you have to have territory under your control. So that matters, in that regard,” the admiral explained.

Airstrikes Affecting ISIS Tactics

But the more critical measure of success is one that can’t be easily quantified: how ISIS’s behavior on the battlefield has changed since the start of the bombing campaign last June, Kirby said.

“We know that they are operating and communicating in much different ways now than they were seven months ago. They’re no longer out in the open,” he said.

Because there are fewer targets, the air campaign has slowed down, the admiral said.

“One of the reasons why maybe there’s fewer targets is because they’re hiding more,” Kirby said. “And if they’re hiding more, if they’re constrained, then they’re not as able to enact the same kind of influence. So they’re changing the way they operate. They are definitely much more on the defensive.”

ISIS forces have also slowed their attempts to seize more territory, he said.

“What we are starting to see them do is defend, you know, so they’re getting into defensive positions on territory that they do have,” the admiral said. “And they are — we’re seeing them try to protect their own lines of communication.”

Progress Against a Potent Force

These signs of progress — in addition to indications that ISIS is struggling due to the inability to resupply themselves and because of the loss of oil revenue — shouldn’t be taken to mean that they are no longer a potent force inside Iraq and Syria, Kirby said.

“There’s a long way to go here,” he said. Establishing the conditions that will lead to good governance inside Iraq and Syria will take three to five years, the admiral said, and eradicating the ideology of ISIS will require more than just a military campaign.

“I’ve said it before, I’ll say it again: … The real center of gravity for this group is their ideology, not their fighters, not their trucks, and not necessarily, you know, every little camp they set up or position that they establish,” Kirby said.

“It’s about this ideology and that’s going to take time. And it’s not going to be done through military means alone.”