Let me just respond quickly to William Marina's points.
For me, Rockwell's piece was worthwhile more for its general argument than all of the details. I'm the first to object to the bandying about of "fascism" as a synonym for "whatever I don't like." And his use of "almost totalitarian" to modify "statist nationalism" is hyberbolic (although "statist nationalism" is right on).
What he's quite right about though is the "takeover" of US conservativism by its statist/nationalist/"statecraft" wing as opposed to its more libertarian leaning one. When the religious conservatives, and the hawks, and the George Wills and Bill Bennetts are all on the same page, and that page is one that is about the glorification not just of the nation but of the state, particularly its military, you know we're in trouble. It's more troubling that a number of self-described classical liberals have gone down the hawk/nationalist path as well. It's not just that the more libertarian-leaning conservatives were out-numbered or out-maneuvered for power in the movement, it's that a good number of them swallowed the Kool-Aid.
In addition, conservativism appears to be much more bound up, as Rockwell says, in the belief good leadership rather than in institutional checks and balances or reform. Just as W believes that because his intentions are good, he has made no mistakes, so do many conservatives appear to believe that if the right people are in power, all will be well. It is supremely ironic that conservatives would adopt the same logic that Keynes did in his "response" to Hayek's The Road to Serfdom.
More generally, Rockwell's point that the threats to liberty are increasingly coming from the right, and that libertarians should be looking leftward for coalition building, is one that I think is correct, even if he somewhat overstates the size of the threat and the promise of real cooperation from the left.
I guess I'm just really tired of seeing libertarians bending over backward to make excuses for modern American conservativism. In the mid-90s, that was at least plausible when the more libertarian-leaning elements of the conservative movement were more at the forefront, but now, with the statist-nationalist elements clearly in control, it is not clear at all what libertarians gain by any alliance with conservatives (and Sudha Shenoy's comments on my original post are very much to the point here). In the world we now live in, it may well be true that on the margin, libertarians have more to fear from an increasingly militarized right than a weakened and drifting left.