I'd rather take a 1/2 full glass, than nothing. That's a major difference between Conservative GOPers and Libertarians.
To me, the difference between conservatives and libertarians is only in matter of degree. The leftists like to define conservative in terms of how they like to "conserve" the authority government has, as if they really believed in liberal policies. In my opinion, there aren't any "liberals" remaining in the so-called left, and what passed for liberal today is synonymous with Marxist. I don't think there's anyone here who would object to the idea that Marxism is all about conserving governmental authority to rule people's daily lives. They make a big fuss about how "liberal" they are, but what they really want is plenty of government authority to make things turn out the way they want.
In that sense, "conservatives" are more liberal than so-called "liberals" or leftists or whatever you want to call them. Conservatives still believe in the idea of a government limited by its charter, however many pragmatic departures they may have made. It isn't that conservatives want government to do or not do certian things, it's just that they agree in principle that the governing charter needs to allow the government to do those things that separates them from "liberals" or Marxists.
That's why I said that libertarians (or more correctly, liberals) and conservatives are separated by differences in degree, and get in all sorts of fights over where that line of government intrusion should be drawn. There's no argument that this line of constitutional restraint be drawn, only where the borders lie. Generally speaking, this is why I get along better with conservatives than socialists; I can always get a conservative to agree in general with constitutional principles and a republican form of government. A leftist on the other hand can never be beated back into a corner in which they must agree that there should be any restraint on government so long as that government is doing good.
That's why I define "conservative" not as the lefitsts do as someone who believes in conserving governmental power or as the Marxists do as someone who believes in the power of the monied classes, but someone who believes in the conservatives application of governmental authority. Once upon a time, those people were called liberals. They were liberal, because they actually believed that governmental authority ought to be limited in the first place. Before two hundred odd years ago, such a concept was quite radical.
In conclusion, I don't think that conservatives and libertarians are all that alien to each other. However, the majority of more moderate libertarians today would seem to have returned to the Republican Party, leaving the Libertarian Party to the few hardnoses that are left.