To be fair to Jason, I have made stronger statements in other threads.
While I have never actually equated them, I do feel it is demonstrable that the modern Libertarian movement IS a direct philosophical descendant of the philosophies that were invented by the pro-Slavery extremists prior to the Civil War, and therefore, Libertarian philosophy and White Supremacy can be said to be, philosophically, cousins. Furthermore, it is also undeniable that American White Supremacist practice and philosophy heavily influenced Nazism.
My feeling is that the average Libertarian probably comes to the party from the anti-government direction, rather than the White Supremacist, probably not understanding the common origin of them both.
The common origin is of course the extreme 'nullification' philosophy that came out of South Carolina, and the South generally, prior to the Civil War. It held that property is the most important basic right, and government can NEVER interfere in a citizens (read, white man's) property (read, slaves). Go through this ideology, remove references to race and slavery, and you will essentially have the Libertarian creed. Go through it and instead remove the legal arguments, and you will have a White Supremacist pamphlet. This is my view on the matter.
The practical effect of this kindred spirit means that white supremacist will feel at home among libertarian groups, and won't be easily detected and rejected by them. Also, one can't help but think with the recent resurgence of white supremacy in this country, that there had to be plenty of people who just a few years ago would have seemed perfectly innocuous to everyone, including myself, but who were in fact hidden white supremacists. (though in hindsight, many signs were there, only I didn't care to see them) I propose that many of them were concealed among the libertarians, though of course the libertarian movement is simply not large enough to have concealed them ALL. Obviously, many were hiding among other groups.