Chris Hayes' brief Nation piece on the Ron Paul campaign is excellent at illustrating the limited relevance of ideology in politics:
Self-identified libertarians may be a tiny portion of the electorate, but small numbers have never stood in the way of bitter intramural sectarian disputes. When Lindsey says that Paul "comes from a different part of the libertarian universe than I do," he's referring to the libertarian version of the Trotsky/Lenin split, which opened up in the early 1980s and continues to echo through libertarianism today.
Assuming he meant the Trotsky/Stalin split, the interesting thing about the way Hayes spells this out is that it ends up being an almost entirely sociological divide between populist types in the provinces and elites in the nation's capital. There are, of course, disagreements about politics and policy within the libertarian camp (like all camps) but it's hard to pinpoint a systematic disagreement about ideas here, it's more a question of different kinds of people.