The Obama administration insists the Islamic State is not an Islamic state, but the Pentagon says it has achieved success against the terror group by treating it like one.

American leaders from President Obama on down reject the Islamic State's core claim of being a "caliphate," a self-proclaimed Islamic nation that stretches from Syria to Iraq.

In terms of military planning, however, defense officials have inflicted their greatest punishment on ISIS after changing their approach from one used against groups like the Taliban to one they might use against another full-scale military.

"We're now entering a different strategic era," Defense Secretary Ash Carter told cadets this week at the U.S. Military Academy, following years of a "very singular focus" on counterinsurgency.

That was the prism through which the military viewed ISIS when it returned to Iraq in 2014 to help Baghdad fight the terror group, and then later expanded operations into Syria. American and international aircrews flew overhead looking for targets of opportunity, such as groups of fighters or people driving captured armored vehicles.

That was effective at first, U.S. officials say, but when ISIS changed its behavior to offer fewer targets, critics charged that Obama and his commanders weren't doing serious damage.

At the time, retired Air Force Lt. Gen. David Deptula, who directed the air campaigns in the first Gulf War in 1991, told NPR the air attacks were "anemic" and likened what he called the administration's "incomplete strategy" to mismanagement of the war in Vietnam.

Changing The Approach

Since then the Pentagon has changed its approach. Even if political leaders don't acknowledge the Islamic State is one, military commanders have found that they can deliver more punishment by treating it like a traditional enemy government – even in their language.

"We are systematically eliminating ISIL's cabinet," as Carter told reporters on Friday, using the acronym preferred by the administration and the military.

Haji Imam, a man killed recently by Americans special operations soldiers, was ISIS's "finance minister," Carter said. Omar al-Shishani, whom the Pentagon says died after an airstrike in Syria, was ISIS's "minister of war."

And the Pentagon's strategy is broader than targeting individual leaders. After Delta Force troops raided the home of an ISIS leader last year who helped lead its black market sales of oil, commanders used what they learned to order a systematic series of strikes against its petroleum network.

Inspired by World War II's Operation Tidal Wave, in which Allied bombers targeted the oil refineries that supplied Nazi Germany, the Pentagon named its similar campaign against ISIS Operation Tidal Wave II.

Hitting Economic Resources

American warplanes have struck some 117 targets related to ISIL's petroleum infrastructure, said spokesman Col. Steve Warren, including eight so far this month.

"It has hamstrung their ability to fund terror operations," Warren said.

Another plank of the military's new strategy has been to keep ISIS from paying its adherents in Syria and Iraq. So not only did U.S. special operations soldiers pursue ISIS's "finance minister," American warplanes are destroying the buildings believed to store the Islamic State's cash, taking away its ability to make payroll.

The Pentagon claims all this is having an effect.

"The momentum of this campaign is now clearly on our side," Carter said Friday.

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