Sen. Lindsey Graham, a Republican from South Carolina, reacted to Iran's attack on two Iraqi bases housing American troops on Fox News this evening.

“This was an act of war, Sean, by any reasonable definition,” Graham told host Sean Hannity. “The President has all the authority he needs under Article II to respond and how he responds is yet to be determined, but he has that authority to respond.”

Graham ended by saying he had just gotten off the phone with President Trump.

"Let me say tonight, if you are watching television in Iran, I just got off the phone to the President: your fate is in your own hands in terms of the regime's economic viability. You continue this crap you're going to wake up one day out of the oil business," Graham said.

Moments earlier, Graham noted that Trump could opt to respond by hitting either military or oil targets.