There’s new fallout from President Obama’s decision today to send up to 300 military advisers to Iraq.

On last night’s Kelly File, Megyn challenged former Vice President Dick Cheney about the Iraq invasion and his criticism of President Obama. He defended the decision, saying it would’ve been “irresponsible” for the United States not to act.

Whatever the merits, Megyn pointed out that great progress was made in Iraq. In 2010, Vice President Joe Biden said Iraq would be one of the great achievements of the Obama administration.

Since the American combat mission in Iraq ended, the situation rapidly spiraled downward and in recent weeks, ISIS militants have taken over key cities and an oil refinery.

National Review contributing editor Andrew McCarthy weighed in on tonight’s show. He said, “The detour that went wrong was the idea of trying to turn Iraq into something resembling a Western democracy, which I think was a fool’s errand in the end.”

McCarthy said the major problem in Iraq is Islamic supremacism. “That’s not a creation of either Obama or Bush. That’s just a fact of life in that region.”

He went on to defend President Obama’s decision to pull American combat troops out of Iraq.

Citing recent poll numbers and some politicians, Megyn said, “Mr. Obama’s critics say […] if we could’ve kept some more [combat troops] on the ground there, we could have protected the gains that 4,500 Americans sacrificed their lives to make."

John Bolton, former U.S. ambassador to the United Nations, called that criticism “irrelevant” to the circumstances we face now.

Megyn responded, “Actually, it is relevant to a lot of people who are out there wondering how did we get here? Is it not relevant to ask how did we get here?”

Bolton said he could care less what the poll numbers say because the issue is what we should do to protect American interests. 

The latest on the unfolding situation in Iraq from Fox News: 

'I'd Let It Burn': Col. Hunt on the Iraq Crisis

Krauthammer: Mistake for Obama to Say U.S. Will Not Send Combat Troops to Iraq

'He Should Do Nothing': Judge Nap Reacts to Obama's Actions on Iraq