Ron Paul, left, father of Sen. Rand Paul introduces his son during a campaign event last month in Iowa City. (AP Photo/Paul Sancya)

SALEM, N.H. -- In a sign of just how tricky it is to court libertarian Republicans here, and how diffuse Ron Paul's old supporters have become, the former Texas congressman took to Fox News Friday to criticize Sen. Ted Cruz (R-Tex.).

"They think he's for the free market, and he's owned by Goldman Sachs," Paul said. "He and Hillary have more in common than we have with Trump or anyone else."

The "we" in that sentence was Paul's son Sen. Rand Paul (R-Ky.). Rand Paul's Wednesday exit from the presidential race kicked off a scramble for the sort of voters who gave almost a quarter of the 2012 Republican primary vote to Ron Paul. Since then, supporters of Rand Paul have been contacted by emissaries of Cruz and other candidates, and many have balked.

"I'm toying with endorsing Cruz, but it's a pill that does not go down easily," said New Hampshire state Rep. Eric Eastman (R). "It's a pill that goes down sideways. Cruz and Trump sent their emissaries, as did Carly Fiorina. Each of them tried to relate their guy's positions, but none of them could really succeed. The fact of the matter is the sense of principle and ethics that the Paulians embrace is not mirrored by any of the other candidates."

Cruz had frequently praised Ron Paul -- a Texas constituent. But in an interview earlier this week, Paul told The Washington Post that Cruz was a "fake libertarian" who did not deserve support from voters worried that Rand Paul was slipping.

"He's associated with the groups we talk against all the time, the neoconservatives," Paul said. "We believe they're the ones associated with so much of the killing in our foreign policy."

Since then, some Rand Paul supporters have received calls from an entity they could not name but suspected was a super PAC supporting Cruz.

"It was very brief," said a Rand Paul supporter named Brandon Ross, "something to the effect of, 'Since Ted Cruz has proven that he's a defender of the Constitution, can he count on your vote on Tuesday?' Something like that. I responded that I didn't think that was proven at all, thanked her for the call, and disconnected... how Cruz's Super PAC got my name and that number so quickly? I don't know. But it's definitely creepy."

The highest-profile jump from the defunct Rand Paul campaign came late Wednesday, when the senator's New Hampshire-based national strategist Michael Biundo joined the campaign of Gov. John Kasich (R-Ohio). At an event in Hollis on Friday, Kasich told a voter who'd driven from Maryland to New Hampshire that he could earn old Paul supporters with the record he'd built in Columbus.

"Criminal justice reform? We've done it in Ohio," said Kasich.

Diehards like Eastman were looking more at the "civic philosophies" of the candidates, and did see points of agreement between the Pauls and Cruz. But Eastman said that Ron Paul's criticism might keep people from joining Cruz's campaign.

"It's fairly brazen choice of language, but that's one of the reasons we loved Ron Paul so much," said Eastman. "You know when he makes a sweeping statement, he had empirical knowledge backing it up."

Two hours after admitting that, Eastman strolled into Cruz's final rally before the primary debate, talking to voters, then sidling up to the stage where the senator would speak. Rep. Bill O'Brien, who had personally lobbied "Paulian" representatives to back Cruz, encouraged Eastman to lead the Pledge of Allegiance. Then, dropping his reluctance, Eastman quoted Mick Jagger -- "you can't always get what you want" -- and praised Cruz's vote against the National Defense Authorization Act.

Cruz took the stage shortly thereafter. "Thank you, Eric," he said. "We are seeing so many Rand Paul supporters, so many leaders in the liberty movement, coming behind this campaign."