Story highlights Rand Paul is visiting many college campuses to advance his libertarian agenda

Paul faces a challenge in wooing young people without alienating other Republicans

Paul is a potential 2016 Republican presidential contender

Campus politics aren't always a clear winner for Rand Paul, as he discovered here this week during an appearance at the College of Charleston.

The Kentucky Republican and potential 2016 contender opened with a familiar riff about government surveillance that won predictable applause -- especially from the many students who represented Young Americans for Liberty, the libertarian outfit created from the ashes of his father Ron Paul's presidential campaigns.

Then a young woman in the audience asked if Paul, who sponsored an anti-abortion bill in 2013 that defines life as beginning at fertilization, is opposed to Plan B, the emergency contraception commonly known as the morning-after pill.

A number of social conservatives -- plenty of them in Iowa -- have condemned the morning-after pill as an on-demand abortion drug, sometimes confusing the contraceptive with RU-486, which can be used to induce abortion.

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Noticeably uncomfortable with the question, Paul first gave a terse answer: "I am not opposed to birth control," he said. After a pause, he elaborated. "That's basically what Plan B is. Plan B is taking two birth control pills in the morning and two in the evening, and I am not opposed to that."

Next question.

The exchange was notable because it happened on a college campus -- a place where Paul has made inroads in building support for his libertarian agenda. And it underscored the challenge that lies ahead for him: burnishing the libertarian credentials that make him so appealing to young voters while making sure he doesn't stray so far from the Republican line that he won't be able to win the party's presidential nomination.

Another student here pressed him on "the drug war," asking if Paul would support legalizing marijuana, cocaine and heroin. He said he wasn't supportive of drug use, explaining that pot "is not that great," but said drug laws should be left up to states. Colorado and Washington are experimenting with legalized marijuana, he said, and we should be watching carefully.

Paul has enjoyed plenty of success on the campus circuit.

His visits to universities from Harvard to Howard have snagged flattering headlines and pats on the back from Republicans who want to modernize the party and broaden its national appeal.

"Rand Paul, Republican presidential hopeful, finds support in Berkeley, of all places," the San Jose Mercury News announced after Paul visited in that den of Bay Area liberalism in March.

Paul, reared in libertarian politics, found support there because he railed against the National Security Administration's invasive surveillance operations, calling them an absurd violation of privacy. It's his go-to topic when he talks to young people.

Last March, at the annual Conservative Political Action Conference, Paul blew his opponents away in a presidential straw poll after he brought a ballroom full of 20-somethings to their feet with cries of outrage over government prying into cell phones.

Soon after, he packed a nearby restaurant with fawning college kids at an open bar sponsored by his political action committee. Paul and his wife, Kelley, danced and sang along to Chumbawamba, the 90s-era pop band with an anarchist streak.

We tagged along to the event at the College of Charleston for the latest episode of "Hambycast."

After the talk, standing in the sun-splashed campus courtyard, I asked Paul to elaborate on some of the issues that so often put his party at odds with young people — as well as the thorny topics that Paul confronts as he tries to square with small-government libertarian roots with a more dogmatic Republican Party.

On the topic of drugs, I picked up where the student left off, wondering if Paul, as president, would allow a state to legalize a hard drug like cocaine or heroin. He hedged.

"My position has not been for legalization, my position has been for less criminalization and more fair adjudication for people that are caught in this, and that kids who make youthful mistakes should get a second chance," he said.

Then I asked about same-sex marriage, something Paul did not touch on in his remarks. Almost 80% of people under the age of 30 support same-sex marriage, according to a Gallup poll earlier this year. It's hard to think of an issue on which Republicans are more out of step with America's youth. And it's not just teenaged and 20-somethings: A clear majority of Americans, 55%, support same-sex marriage.

Paul favors traditional marriage, but has said states should determine their own marriage laws.

"I don't want my guns registered in Washington or my marriage," he told me. "Founding Fathers all got married by going down to the local courthouse. It is a local issue and always has been."

But can Republicans win a national election if they aren't in tune with rapidly changing opinions on the matter? He took a soft tone.

"Society's changing," he said. "I mean, people change their minds all the time on this issue, and even within the Republican Party, there are people whose child turns out to be gay and they're like, oh well maybe I want to rethink this issue. So it's been rethought. The President's rethought the issue. So I mean, a lot of people have rethought the issue."

It sounded, for a moment, as if Paul was hinting that he, too, could change his thinking about marriage.

"The bottom line is, I'm old fashioned, I'm a traditionalist," he said. "I believe in old-fashioned traditional marriage. But, I don't really think the government needs to be too involved with this, and I think that the Republican Party can have people on both sides of the issue."

"You could rethink it at some point, too?" I asked him.

He shrugged, and gave me a half-grimace. It wasn't a yes or a no, but it revealed Paul's complicated dance as he tries to color outside the lines of the Republican Party.