The Pittsford Perennialist says as much in the title of this post: Pope Ratzinger, Libertarian. I think that the proprietor of that blog is overstating his case a bit, though. Benedict XVI is no libertarian, although I think it is fair to characterize him as somebody with profound concerns regarding the limitation of coercive state power. This, of course, is a result of the experience that Ratzinger went through as a young man, enduring life in totalitarian Germany under the Nazis.
But a concern over the limitations of the state does not a libertarian make. In addition to a commitment to limited state power, there must be a corresponding commitment to the notion of individualism and social atomization. And Ratzinger displays neither of those ideas. Indeed, if one looks at the political party within Germany most closely aligned with the American idea of libertarianism -- the Free Democratic Party -- it is difficult to characterize Ratzinger as libertarian.