In a series of tweets Wednesday afternoon, Cato Institute Vice President of Research Brink Lindsey called Ron Paul a xenophobe, conspiracy theorist, and Paul’s philosophy a “hideous corruption of libertarian ideas.”

In two back-to-back tweets, the Cato VP stated that “the most prominent libertarian voice of recent times, Ron Paul, opposed all trade agreements and promoted anti-trade conspiracy theories” and “Ron Paul’s xenophobia was a hideous corruption of libertarian ideas and puts his movement in the Trumpism family tree.”

Following his attack on Ron Paul, Lindsey also attacked libertarian theorist and luminary Murray Rothbard, whom Ron Paul had called “the founder of the modern libertarian movement.” In the tweet, Lindsey blamed Rothbard for the “ugly illiberal streak” within the libertarian movement:

This is not the first time that Lindsey attacked Ron Paul or the people surrounding him. In a 2007 article authored by Chris Hayes for The Nation, Lindsey described Ron Paul supporters as “a weird group of people,” consisting of libertarians, anti-war types, nationalists, and “xenophobes.”

Brink Lindsey has a long history of promoting views at odds with the grassroots libertarians, “xenophobes,” and “anti-war types” he derides. For example, in 2002 Lindsey expressed his support for the Iraq War, the 1991 Gulf War, war in North Korea, and other globalist interventions in Reason, stating that he “would support military action against Iraq even if 9/11 had never happened and there were no such thing as Al Qaeda.”

The root cause of Lindsey’s disagreement with libertarians like Ron Paul and Murray Rothbard is their support for a libertarian alliance with the right-wing. In a short article published in Reason in 2010, Lindsey argued that “Libertarians need to disengage from Republicans and conservatives once and for all.”

In “Liberaltarians,” an article written for The New Republic in 2006, the Cato VP championed the “progress” liberals made on issues like secularization of society, legalization of abortion, and increasing immigration. He also, however, erroneously predicted that “the movement’s ‘fusionist’ alliance between traditionalists and libertarians appears, at long last, to be falling apart.”