No surprise here, as Paul's supporters worked hard to get out the vote for their man.

Robert Costa:

Rand Paul won the straw poll at the Conservative Political Action Conference on Saturday, a victory that cements his status as a tea-party favorite.

Paul, who spoke at CPAC earlier this week, drew the support of many college-age activists and libertarians. Throughout the conference's hallways, the support for Paul was strong, and his backers handed out "Stand with Rand" posters.

Conservative leaders say Paul's victory is a sign of his popularity within Republican ranks. "I'm glad someone who says bold things is rising," says Arthur Brooks, the president of the American Enterprise Institute. "At a time when many conservatives are reflecting on the future, his views are connecting."

Boyden Gray, a former counselor to President George H. W. Bush, agrees. He says Paul may not be cheered in every corner of the party, but he's a formidable figure. "Even within the GOP, people are beginning to question big institutions, from big government to big banks, and Rand Paul is speaking to them," he says.

Senator Paul, a Kentucky Republican and ophthalmologist, follows in the footsteps of his father, Ron Paul, who won the CPAC straw poll in 2010 and 2011.

Paul's supporters were not the only activists pushing a candidate at the Gaylord National Hotel in suburban Maryland. Supporters of Rick Santorum, a former Pennsylvania senator, and supporters of New Jersey governor Chris Christie also had informal get-out-the-vote operations.

But Paul's group was, by far, the most vocal, and its efforts paid off. According to a CPAC official, Paul was expected to win, and he drew heavy, consistent support. 

Other Republicans on the ballot included Senator Marco Rubio, Senator Ted Cruz, Governor Bobby Jindal, and Governor Scott Walker. Rubio, for his part, came in a close second. Paul won 25 percent, and Rubio won 23 percent.

Tea Party favorite, rising Republican star, libertarian heartthrob - but a successful candidate for the GOP nomination in 2016?

It won't be his fiscal conservatism, or his ability to articluate conservative principles. But it may be his foreign policy positions that would make Rand Paul a bridge too far for a majority of Republicans. Is the party ready to accept isolationism as a foundational principle in foreign affairs? This remains to be seen.

Rand Paul is not as stridently anti-interventionist as his father and that has to count for something. But you can bet the major line of attack of Paul's primary opponents will be questions about his commitment to Republican foriegn policy principles.