Ron Paul, the former congressman and GOP presidential candidate, is finally joining his son Sen. Rand Paul on the 2016 campaign trail.

The two will appear together January 31 at the University of Iowa, just a day before the critical Iowa caucuses.

As a staunch libertarian, Ron Paul inspired a strong coalition of young supporters during his own White House bids, and he is credited with helping to ignite the tea party movement. The reach of his presidential campaign, however, was limited. In 2012, Paul's campaign finished third in Iowa, behind former Pennsylvania Sen. Rick Santorum and the eventual GOP nominee, Mitt Romney.

Rand Paul has walked a fine line since launching his own presidential campaign, attempting to win the support of his father's enthusiastic supporters while appealing to a broader audience.

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"Together they will focus on energizing the youthful base by discussing the importance of protecting the entire Bill of Rights and being boldly for conservative ideals that limit the powers of the Washington Machine," Rand Paul's campaign said in a press release announcing the January 31 event. "Rand's unique message of liberty can unite Constitutional conservatives, young voters, and independent voters, which will lead to a successful showing on caucus night."

Earlier this week, Ron Paul said in an interview that it "certainly is realistic" at this point that Donald Trump will win the GOP nomination. The media, he said, has "generally rigged" the contest. "They pick people, they boost them up. It's entertainment. And Trump really fitted into that quite well," he said.

While Trump appears to be on his way to securing the nomination, Ron Paul said his son "may well surprise everybody because he has good organization and caucus states are different."