In what can only be another harbinger of bad news for Sen. Rand Paul’s troubled presidential campaign, one of three pro-Paul super PACs has stopped raising money for the Kentucky Republican, with its leader calling it “a futile crusade.”

Ed Crane, who leads PurplePAC, told Politico Tuesday that he won’t raise money until the campaign changes course.

Crane, a co-founder of the libertarian think tank Cato Institute, told the site: “I wasn’t going to raise money to spend on a futile crusade. … I don’t see the point in it right now.”

He also credited Paul’s fall in the polls to running away from the libertarian views that vaulted the senator to popularity in the first place.

“I want to grab Rand by the lapels and say, ‘What are you doing?’” Crane continued. “I’m a big fan of Rand Paul. But whatever motivates his campaign, I don’t get it.”

Paul has steadily fallen in recent polls and run into money trouble on the way down. He managed to raise just $13 million between his campaign and the PACs, a figure dwarfed by one PAC backing former Florida Gov. Jeb Bush that raked in $103 million in the first six months of 2015.

GOP frontrunner Donald Trump has hammered Paul for his low poll numbers, and predicted before the news Tuesday that Paul would soon bow out of the 2016 race.