No, probably not. He called himself a socialist. But his satires of war and government often sounded libertarian themes. One libertarian argues that his 1952 novel Player Piano, though usually understood as a critique of technology and automation, can also be seen as a prescient criticism of “neocon America,” in which “the centralization of corporate/government power over the economy and security forces is a legacy of the last war, which was largely responsible for putting engineers and managers in charge of a command economy.”
And he did write one of the great libertarian short stories, “Harrison Bergeron,” the story of a world in which the U.S. Handicapper General gives everyone “handicaps” in order to make us all equal–masks for the beautiful, weights for the strong or fast, buzzers in the brains of the smart. The tagline of the 1995 Showtime movie starring Sean Astin and Christopher Plummer was “All men are not created equal. It is the purpose of the Government to make them so.”
Socialist or not, we could use more satirists and fewer red team/blue team party-liners. We will miss Kurt Vonnegut.