A great quote from Bryan McGrath in Information Dissemination:
Libertarianism strikes me (and others) as a fine bit of political ideology when alloyed with other ideologies. Their preference for dramatically limited government helps pull Conservatives to the right, and the preference for removal of government from the private sphere appeals to many Liberals seeking to advance social policies. Unalloyed however, Libertarianism is a quaint, interesting, and ultimately unsuitable approach to governing a modern Republic, especially a world power.
I wouldn’t limit that to Libertarianism. I’d extend it to all ideologies.