Brink Lindsey and Will Wilkinson are the two most prominent "liberaltarians" -- libertarians who believe they have more in common with liberals than conservatives. Both have just announced their departure from the libertarian Cato Institute.

I haven't seen any hard data to prove they were purged. But this column by right wing-libertarian Tim Carney basically takes it as a given that they were purged, and argues they had it a-comin':

[L]iberal-tarianism - it's not working out so well.
That's certainly part of why Cato higher-ups were done buying what Lindsey was selling. But the liberal spin on the breakup struck some libertarians as true - and that's cause for concern politically.
Libertarian donors tend to be small-businessmen, and when they look at the nation's increasing debt, regulation and taxes, they begin to see Obama as the devil.
Obama's excesses are making free-marketeers more partisan. The same entrepreneurs who two years ago cursed Republican overspending and Bush bailouts are now asking one question: How can we drive Obama, Pelosi and Reid from power?

Carney's column is mostly a justification of purging Lindsey (and Wilkinson, I suppose, though he goes unmentioned.) Carney argues that the Democrats are so wedded to big government that libertarians have to side with the GOP. Of course, that depends entirely on your perspective and value system.

Indeed, as Lindsey have argued, it's entirely possible to conceive of a libertarianism that's situated on the left. I'm not exactly a fan of that ideology, but it's coherent. But here is where the role of money comes in. Libertarian institutions are funded by businessmen, who steer them toward emphasizing the parts of their agenda that dovetail with the interests of business and the rich. Thus Cato is deeply committed to promoted climate science skepticism. Jane Mayer's great New Yorker piece about the Koch brothers, who fund Cato, Reason, and many other right-wing and libertarian groups, has a telling quote:

Many of the organizations funded by the Kochs employ specialists who write position papers that are subsequently quoted by politicians and pundits. David Koch has acknowledged that the family exerts tight ideological control. “If we’re going to give a lot of money, we’ll make darn sure they spend it in a way that goes along with our intent,” he told Doherty. “And if they make a wrong turn and start doing things we don’t agree with, we withdraw funding.”

The role of libertarian institutions in American politics is primarily as a place for members of the conservative movement with left-wing views on social issues and/or foreign policy. They could easily play a different kind of role, but they don't.