WASHINGTON -- Florida Sen. Marco Rubio outlined his approach to foreign policy Wednesday at the Brookings Institution, giving a speech that carries more weight now that he’s thought to be on Mitt Romney’s shortlist for vice president.

The address offered a new vision of the senator, one that shows him as more than a Cuban-American politician with the skills to sell Hispanic voters on the Republican Party.

Rubio said the easiest thing he could do during his address would be to criticize President Barack Obama’s foreign policy. He still took a hard whack, saying the Obama administration must commit more firmly to a world leadership role. He was especially critical of what he called the administration’s over-reliance on global institutions such as the United Nations to engage in places such as Libya. Syria, he said, is "waiting for American leadership."

"I disagree with the way in which the current administration has chosen to engage," Rubio said in prepared remarks. "For while there are few global problems we can solve by ourselves, there are virtually no global problems that can be solved without us. In confronting the challenges of our time, there are more nations than ever capable of contributing, but there is still only one nation capable of leading."

In introducing Rubio, Sen. Joe Lieberman, a Connecticut independent, called his fellow senator’s foreign policy "principled, patriotic and practical" and suggested that it emerged from a bipartisan tradition in the Senate.

The moment of bipartisanship, though, was Rubio saying he also disagrees with the voices in his party who say the U.S. shouldn’t engage in the world. Just look no further than the “Kony 2012” video, Rubio said, which introduced millions of people to the allegations of human rights abuses against Joseph Kony in Uganda, via an American invention: YouTube.

"I disagree because all around us we see the human face of America’s influence in the world. It actually begins with not just our government, but our people," Rubio said, according to the prepared remarks. "Millions of people have been the catalyst of democratic change in their own countries. But they never would have been able to connect with each other if an American had not invented Twitter."

Democrats fought back hard. Democratic National Committee spokesman Brad Woodhouse called Rubio’s speech "revisionist history," and said in a statement that it should be viewed skeptically "coming from a man who’s using the opportunity of this speech to audition for another job."

Woodhouse ticked off a list of Obama administration accomplishments, including bringing troops home from Iraq, killing Osama bin Laden and decimating al Qaida leadership, imposing sanctions on Iran and providing Israel with what he called "the largest security assistance package in history."

"Under President Obama’s leadership, we have successfully confronted our enemies and strengthened our alliances to effectively meet the challenges we face overseas," Woodhouse said.

Rubio’s speech was a fine-tuned version of the one he’s been giving since last year, when he began ramping up his speaking engagements with an address at the Ronald Reagan Presidential Library in California, and a separate speech on foreign policy at North Carolina’s Jesse Helms Center.

Now, though, people are paying more attention. Rubio joined Romney on the campaign trail this week in Pennsylvania for a town hall that had the appearance of a tryout for the vice presidential job.

Rubio also has substantially more foreign policy under his belt than he did even a year ago. He visited Libya in September, he visited Haiti this winter and he attended the Summit of the Americas in Colombia earlier this month.

He’s also been a vocal critic of Obama’s engagement with Latin America and Cuba, going as far as to object to the top State Department official for the region, Roberta Jacobson, until the administration talked to him about his concerns.