Sen. Marco Rubio, R-Fla., outlined his ideas about the challenges facing America’s next president. He wouldn’t say if he’ll be among the field of 2016 presidential contenders.

Appearing on CBS News’ “Face the Nation” this morning, Rubio said that regardless of who enters the race for president, the No. 1 issue facing the candidates will be U.S. national security:

At a time when we’re facing threats from rising powers like China, that want to rewrite the global order, like Russia, that want to ignore the global order, to rogue states like Iran and North Korea, who want nuclear weapons to be immune from the global order, and radical Islamists, that want to have a brand new global order in which everyone lives under the flag of radical Islam. That’s the first threat we face, and we need a commander in chief who understands the nature of the threat, and has real ideas about how to address it.

Rubio said “the radical transformation of our economy” remains an important issue as well.

“We need new, modern policies to give everyone an opportunity to succeed,” Rubio said. “I believe the next president of the United States needs to be someone who understands the 21st century, and the opportunities of this century, so that everyone can make it to the middle class and beyond.”

Rubio criticized President Obama’s plan to provide free community college by increasing taxes on the wealthy as an “outdated” product of the last century and called the notion that “in order for someone to do better, someone else must do worse” false.

Rubio made clear that he has not yet made up his mind about running for president.

“If I decide to run for president,” he said, “and I’m very seriously thinking about it because of where our country is today, I’m going to go out and run a campaign where I’m going to explain to people not only do I understand the national security threats that we face, but that I believe that we need to turn the page and fully embrace all the opportunities and confront the challenges of a new century.”