IME he is pretty much worshipped by the libertarian crowd, but not taken seriously in the mainstream. His son Rand Paul seems to be taken more seriously, but libertarians seem to have extremely mixed opinions of him, since he is more of a pragmatist than his father (which they interpret as compromising on core values). Note: I am not a libertarian, but I have many friends who are deeply involved with the movement, so this is my rough view from afar.