“The next president of the United States needs to be someone that has a clear view of what’s happening in the world, a clear strategic vision of America’s role in it, and a clear tactical plan for how to engage America in global affairs,” the Florida senator said to reporters at a Christian Science Monitor breakfast in Washington. “And I think for governors, that’s going to be a challenge initially because they don’t deal with foreign policy on a daily basis.”

The country’s national security, he said, is the “central obligation of the federal government.” It was a subtle dig at his fellow establishment Republicans, two of whom happen to be former governors: former Massachusetts Gov. Mitt Romney and Rubio’s Florida colleague, former Gov. Jeb Bush, who are each openly considering a 2016 bid. And it set the tone for how Rubio will attempt to frame a presidential campaign.

Though he acknowledged that governors have made great presidents in the past, Rubio said that strong national security is the key to any successful administration. Rubio, who sits on the Senate Foreign Relations Committee, alluded to the contrasts between himself and the other candidates, highlighting his Senate foreign policy experience.