DES MOINES — Hours before his return to the main debate stage, Rand Paul met with what he hopes will prove to be his secret weapon in the Iowa caucus: college students.

"Are there any liberty lovers in the house?" the Kentucky senator and 2016 Republican presidential candidate asked the crowd at Drake University Thursday. The mostly young audience, housed in a venue that was at capacity but much smaller than where Donald Trump would later speak on the same campus, cheered wildly.

When Paul went into his stump speech about how Republicans need to be the party for people with and without tattoos, wearing overalls and suits, a young African-American man in a Rand 2016 t-shirt whispered to a campaign volunteer, "He needs to add with and without dreadlocks too."

Trailing in the polls, Paul has been getting back to libertarian basics as the campaign heads into homestretch. He hit liberty movement themes — and his fellow Republicans — hard. "The loudest voices in Washington calling for spending," he said, "are actually right now coming from Republicans."

"Every Republican says they're for balancing the budget, but nobody ever does it," Paul contended. "I've actually introduced three budgets that balance."

Paul also took aim at what libertarians frequently call the "welfare-warfare state."

"On the right, the call is for enlarging the military state," he said. "On the left, the call is for enlarging the welfare state. And the dirty little secret? The dirty little secret in Washington is that the right and the left always get what they want: more spending. And you, you get stuck with the bill."

"The inconvenient truth," Paul later added, "is that you can't be a conservative if you are a liberal on military spending."

Paul has found it more difficult than expected to keep the libertarian base he inherited from his father motivated while also making inroads with Republicans who share his fiscal conservatism but may not agree with him on foreign policy, civil liberties or Pentagon spending.

The careful balance that served Paul so well since winning his Senate seat in 2010 has been trickier to achieve under the glare of the presidential campaign spotlight. He tumbled from his spot in the top tier of candidates last year and failed to qualify for the sixth primetime debate, despite a fifth-place showing in the most current Des Moines Register poll of Iowa. Paul refused to go to the undercard debate.

Fox News brought up these struggles when he was back in primetime. Noting that Ted Cruz's campaign had come out with a video describing the Texas senator as the true intellectual heir to former presidential candidate and Texas Congressman Ron Paul, co-moderator Brett Baier asked, "[D]id you make a mistake by not 'fully', more fully embracing your father at the beginning of this campaign?"

"There is probably no person I respect more in this country or in recent history than my father," Senator Paul replied. "I think he was probably the most honest man in politics that we've ever seen in a generation."

Paul will appear at a rally with his father Sunday night, caucus eve, at the University of Iowa. He also has Saturday campaign stops with Rep. Thomas Massie, R-Ky., one of the libertarian Republicans elected to Congress after the Pauls' success.

For a while, Paul appeared resigned to being a message candidate. He was spending more of his time going after Marco Rubio, the Florida senator whose positions on foreign policy and surveillance most sharply contrast with his own, than criticizing Cruz, who was actively competing with him for votes in Iowa, New Hampshire and Republican Liberty Caucus straw polls throughout the country.

"Imitation is the sincerest form of flattery," Paul told the Washington Examiner on a conference call after an earlier debate, acknowledging that Cruz had moved in his direction on some of these issues and that even Republican front-runner Donald Trump wasn't so bad on questions like whether the U.S. should have pursued regime change in Iraq, "in his own inconsistent way."

But Paul has persistently attacked Trump as a demagogue perverting the goals of the original Tea Party, recently calling him an "orange-faced windbag" who would raise the seventh Republican debate's IQ by "a couple dozen points" with his absence. Lately, he has stepped up his efforts to protect his turf from Cruz.

After praising his father, Paul immediately hit Cruz for inconsistencies on NSA surveillance and failing to show up for a vote on legislation that would require an audit of the Federal Reserve. "And so I really think that [libertarian-leaning Republican] vote is going to stay in the Paul household," he said.

When Paul mentioned Cruz missing the audit the Fed vote at Drake earlier in the day, the crowd booed loudly. There were some chants of "Audit the Ted," as well as the more familiar "End the Fed."

"Ted Cruz sucks!" one youthful Paul supporter jeered. It was a sentiment that seemed to be shared by Paul's vocal contingent of fans in the audience at Thursday night's debate.

In a previous debate, Paul seemed to reinforce Cruz's assault on the Gang of Eight and Rubio's immigration record. The Kentuckian still argued in Des Moines Thursday, "I would say, if you want to defend the country it begins with border security … this is where I've had my disagreement with Senator Rubio."

But he also gave Rubio an assist in his immigration exchange with Cruz, saying that according to his opponent, "Everybody's for amnesty except Ted Cruz." Rubio acknowledged Paul's criticism of Cruz's "authenticity problem" and escalated it by calling it "the lie Ted's campaign is built on."

On the trail, Paul hits all of his primary foes equally as being too eager to start World War III. He chides Cruz for talking about making the sand glow in the Middle East, Trump for loose talk about nuclear weapons, Rubio for regime change in Syria, Chris Christie for wanting to shoot Russian planes down if they violate a Syrian no-fly zone. He tells students he's the only candidate who won't spy on their telephone calls or send them willy-nilly to war.

While Paul stands little chance of replicating his father's 2012 showing in Iowa, with expectations now greatly lowered the campaign sees an opportunity in 10,000 college students and a ground game headed by 1,000 precinct captains. Speakers remind the college crowd that Iowans can caucus at 17 if they will be 18 by the general election and that even out-of-state students can still give speeches on Paul's behalf at local precincts.

Paul is facing some pressure from Republicans at home, now that Lexington Mayor Jim Gray is entering the Kentucky Senate race on the Democratic side. Should he hang up a quixotic White House run and defend his seat instead?

"He's going to shock the world," said Stephen Bader, a young Paul supporter at the Drake rally, adding that people are wrong to count the senator out in Iowa and beyond.

Paul too expressed confidence that his is a "message that can prevail and win the White House." He also offered what could be a consolation to his supporters if he comes up short. Recounting the confrontation with the angry mob in To Kill a Mockingbird, he observed, "The majority's not always right. In fact, the majority is quite often wrong."