That's what I'm going to call the error I sense lurking beneath a lot of resistance to moderate libertarianism. The fallacy is based on an implicit denial of the fluidity of ideology and political identity. The bounds of “right” and “left” have shifted immensely over the past two generations. Yet political conversation at any time tends to proceed as if the ideological inclinations and cultural assumptions of the “left” and “right” are natural, essential, and fixed. So, just to pick an example out of the air, the argument that the considerable intellectual, cultural, and psychological overlap between moderate classical liberals and market-friendly modern liberals ought to be given more coherence as a political philosophy and political identity is invariably met with the claim that this is compltely pointless because these groups have traditionally been part of different partisan coalitions, and these coalitions are essentially this or that way. So in order to make something liberaltarianism a going concern, you've basically got to find enough libertarians and natural Democrats both willing to sell out everything they believe in and good luck with that. It's basically the same reasoning that says it is impossible to introduce to market a successful new brand of cereal because all the preexisting cereals brands already have 100 percent of the market share. But there's something pretty obviously wrong with that way of thinking. I'm a big fan of Kashi U.
Meanwhile, see Matt Welch's puzzling piece on “The Liberaltarian Jackelope.” Matt's argument seems to be that he's totally a liberaltarian, that it once looked as though some Western Democrats might make some electoral headway by taking on a bit more libertarian flavor, and this excited him. But it turned out that Democrats aren't even interested in following the Republicans in using fake libertarian rhetoric for political gain. So liberaltarianism is doomed.