Rand Paul has lost the support of a political action committee run by a co-founder of the Cato Institute.

On Tuesday, Ed Crane announced that PurplePAC, one of three super PACs that supports Paul, has stopped raising money, according to Politico.

Crane said he didn’t have the desire to support a “futile crusade” and accused Paul of distancing himself from libertarian views.

PurplePAC raised about $1.2 million by July to support Paul’s campaign.

Republican insiders expect Paul’s campaign to be the next notable GOP campaign to fold. Paul’s support in the polls have been in decline since the beginning of summer, despite — or because of — his divergent opinions among the Republican candidates vying for the nomination.

The problems of a Rand Paul campaign were prominent from the start. It’s difficult to unite libertarian-minded Republicans and traditionally conservative Republicans under one candidate. The diversity within conservative and libertarian thought in the Republican Party disadvantaged Paul’s attempt.

Paul has struggled to spark the enthusiasm that his father, Ron, did during his 2008 and 2012 presidential campaigns. And, Ted Cruz has attempted to lure Ron Paul supporters to his campaign with some positive results.

The loss of PurplePAC isn’t a devastating blow to Paul financially. Paul needs all the financial support he can get, and Paul’s financial backing is about $13 million including the three super PACs.

The loss of PurplePAC and Ed Crane, however, is a strong blow to Paul’s reputation as a candidate for libertarians.