Sen. Lindsey Graham (R-S.C.) said on "Fox and Friends" that he's leaning toward a presidential bid. 

Graham said it's "more likely than not" that he will throw his hat in the ring for the Republican nomination, adding that he expects to make the final decision in May. 

"The next president of the United States needs to figure one thing out quickly: how to be commander-in-chief. And I think I could do that," said Graham, who has already started raising money for a possible campaign.

Graham said he remains concerned about the Obama administration making a "bad deal" with Iran on its nuclear program. 

Graham said the current proposal would put Israel "at risk existentially" and trigger a nuclear arms race in the Middle East. 

"Ben Rhodes said 'well those who want to stop a deal, want a war.' Ben, I don't want a war. I don't want a bad deal that leads to a nuclear arms race and eventually a nuclear war," said Graham.

With the deadline for an agreement looming, Iran has reportedly made a last-ditch push for additional concessions from the West. The New York Times reported that Tehran had backed away from a tentative promise to ship a large portion of its uranium stockpile to Russia, where it could not be used as part of any future weapons program.