Tonight on “The O’Reilly Factor,” Charles Krauthammer said the nation’s greatest threat could be Iran going nuclear.

Krauthammer said that the Obama administration paid Iran $11.8 billion to engage in six months of negotiations that ended in nothing. Now, the administration is paying another $2.8 billion to get another four months of “useless negotiations.”

According to Krauthammer, even if an agreement is reached, it will leave Iran a nuclear threshold state, meaning it’s between six and eight months from a bomb.

Richard Grenell on Nuke Deal Delay: Iran ‘Being Rewarded for Attending Meetings’

“Terror at the conventional level will give us 9/11. But terror at the nuclear level will give us unbelievable destruction that we cannot imagine, and that would be coming,” he said.

Krauthammer said the world is looking around and saying: where’s America?

“We have a president who says Russia’s on the wrong side of history as if history’s gonna work stuff out without the United States,” he said.

Obama: 'Much More Worried About Nuclear Attack on NYC' Than Russia

He said our allies are unsure if they have someone to back them, while our enemies are thinking they have free reign “because the sheriff has gone home.”

Watch more above.