Indeed, his entire philosophy is largely a renunciation of much of what Republicans believe about America's role in the world. He questions the popular notion of American exceptionalism and has argued in his recently published book, Liberty Defended, that the "United States is an empire by any definition, and quite possibly the most aggressive, extended, and expansionist in the history of the world." This is the kind of language that might cause Ronald Reagan to roll over in his grave.
And that's just for starters. He belittles the war on terrorism as a "cliché" that is used to "con the people into thinking that all citizens must cooperate and sacrifice our liberties to ‘win' the war."