“Our foreign aid is largely built on the idea of compassion—the notion that every human being has native and inalienable rights that are given to them, and we care about those issues. That’s why we engage,” said Rubio. “There are ancillary benefits from a geopolitical perspective, but we’re motivated to act out in the world because it bothers us that people are starving and hungry and people are dying of disease.”

None of this is new ground for Rubio, as some news reports have suggested. He’s been making a similar case for American strength and leadership for years.

If Rubio is the likely 2016 candidate who benefits most from an extended public debate on national security, there are others who could be drawn into the contest because of the prominence of these issues.

In a recent, hour-long interview, Lindsey Graham said if he is reelected to the Senate in November, he will begin exploring a bid for the presidency.

Graham has long been one of the most active and outspoken hawks in Congress. He has been a voluble critic of the Obama administration on a wide variety of national security issues—Guantánamo Bay, Benghazi, Iraq, Syria, Afghanistan, Russia, Iran, and others. Unlike many of his colleagues, Graham often first seeks to engage the administration privately as it debates policy with the hope that he can help shape the outcome rather than just criticize it after the fact.

But Graham no longer trusts Obama enough to engage him on these matters. 

In our interview, Graham repeatedly spoke of the challenges that will face the next president because of the mistakes made under Obama. And he suggested that he might just be the one to fix them.

“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.

I asked Graham about Rubio. Hasn’t he been making many of the arguments you’d be likely to make? Graham wasn’t impressed. “He’s a good guy, but after doing immigration with him—we don’t need another young guy not quite ready,” said Graham. “He’s no Obama by any means, but he’s so afraid of the right, and I’ve let that go.”

McCain likes what he sees in the emerging GOP field, but acknowledges that he’s told Graham to think about running. “I’ve strongly encouraged him to give it a look. I think Lindsey has vast and deep experience on these issues that very few others have. I happen to like a lot of these guys—I like Jeb Bush, Chris Christie. Ted Cruz has gone out of his way to tell people how much he agrees with me on national security.” And Rubio?

“He’s articulate, intelligent, and has all the right instincts. He doesn’t have the background that Lindsey does, but he’s probably as articulate as anyone in our party. I’ve watched him carefully on the Foreign Relations Committee—he’s excellent. Very impressive.”

Stephen F. Hayes is a senior writer at The Weekly Standard.