I think a larger point here is the difference between Lew Rockwell saying that Buchanan, while wrong on economics, is often right on foreign policy, and the LP nominating Barr for President. Lew Rockwell is in no way suggesting that Buchanan is libertarian or that, far worse, libertarians should move themselves to meet Buchanan. Instead, he's pointing out what Buchanan is good at. The LP, on the other hand, is allowing Barr to set the, well, the bar for what a libertarian is, and holding him out as a standard-bearer in general. These are quite different.
I think our educational tactics are quite important. At present, 5% of the population, to be quite generous, would identify at all with libertarianism as a whole. Maybe 10-15% can be brought around with solid education, the Mises Institute, FEE, and so on. This latter number would include all the people brought in by Ron Paul campaigns. If we accomplish what we can, we still, in the short to medium term, cannot exert enough power to make changes. What we can do is be a pressure block. I suggest that libertarians stop acting as if the real dangers weren't present, and start realizing we need to be in defensive mode. We do have large enough numbers that, when non-libertarians pop up talking about the largest current dangers, we can assure them that we bring something to the table. When Kucinich risks losing his career by standing against the war, libertarians ought to acknowledge that. So, I suggest that libertarians do not need to support only pure libertarians, but rather can and should acknowledge others when they make the most important current points. As times change, the people making these points will change. Right now, the most serious concerns are foreign policy and civil liberties, and we would do well to lend our support to anyone who stands with us on these. That includes Buchanan, Kucinich, and Nader, but not Barr.
On the other hand, we would be quite unwise to try to "claim" these folks as libertarians, and thereby dilute what libertarianism means. That is unfortunately what is happening with Barr. We're in defensive mode, and helping these people because they are fighting what we are most worried about. We are not thereby promoting libertarianism, but using our libertarian perspective to press against the most serious dangers to liberty. In the long-term, we also need to build our numbers and press for libertarianism, but that long-term perspective, which I believe is important, should not mean that we do nothing short-term strategically while real things are happening. What we should not do, though, is a short-term attempt to short-circuit the necessary steps by forcibly implementing libertarianism - as by latching onto celebrities to run as Libertarians and attempt to win the election.