Story highlights Sens. John McCain and Lindsey Graham, both Republicans, have long been hawkish allies

Graham unofficially launched talk about him running for President in an October interview

McCain said in an interview published Monday that he's encouraging Graham to run

South Carolina Sen. Lindsey Graham is getting encouragement from a close colleague and friend, Sen. John McCain, to run for President.

"I think he is looking at it, and I am strongly encouraging him to take a look at it," McCain, an Arizona Republican, told ABC News in a story published Monday. "I know of no one who is better versed and more important on national security policy and defense than Lindsey Graham, and I don't think these challenges to our security are going away."

Graham floated the possibility of a run in an interview with the Weekly Standard last month, telling the magazine he'd be interested in running to guide the conversation on national security.

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"If I get through my general election, if nobody steps up in the presidential mix, if nobody's out there talking — me and McCain have been talking — I may just jump in to get to make these arguments," Graham said.

As the libertarian wing of the GOP has gained prominence, led by expected 2016 presidential contender Sen. Rand Paul, members of the party's more hawkish old guard have floated presidential runs to offer a contrasting voice in key national security debates.

This Sunday, however, speaking on CNN's "State of the Union," Graham sounded far from an affirmative decision.

He said running for president is "the hardest thing one could ever do. You go through personal hell. You have got to raise a ton of money. I'm nowhere near there."

If he does jump in the race, he'll add to a Republican primary field that's already likely to include more than half a dozen contenders for the party's nomination. McCain told ABC News that he's all for a broad slate of candidates, and that the race is currently "wide open."

"I think we should let a thousand flowers bloom. I think that the process is wide open right now, and I think not only will members of the Senate be considered, but I think some of our successful Republican governors will also be interested," he said.