This is a very good point and leads well into this important debate going on here on FR and in the greater political world beyond. The question of "what is a conservative?" needs to be answered and then "who" is a conservative falls into place.
So if a conservative wants to "conserve" what is it then that he wants to conserve? Can conservatism be dynamic? Definition of the term would argue against that and that is why the definition is under debate - by changing the definition one changes people's political beliefs. Since humans are a herd animal they identify with and move as part of a group. Individually conservatives would not be susceptible to political change but with an ideological shift in the direction of the herd by trusted leaders they go willingly along without detecting the change in direction. A shift has happened and some have called the shifters to account and this is what the current argument is all about. This is also why the one side throws around the charges of racism and anti-Semitism. These charges are so loaded that they strip the legitimacy of their opponent and thus everything he says. It is a cheap nasty trick to avoid answering policy questions but most importantly it calms the herd - those dissenters are awful, rotten people who "we" would not want to associate with.
As this article states conservatives who say they wish to preserve liberty and limited government hold certain founding fathers - Jefferson, Washington, etc. as their role models. Today's conservatives hold up Wilson, FDR, Truman, LBJ. So if you are a conservative think about those role models and ask yourself what is a conservative today and what it is you individually wish to conserve.
I am no fan of the Lowry-Goldberg hold on NR, however it remains pro-immigration reform.
Mencken and Nock certainly weren't typical conservatives for their day. Most conservatives of the 1920s or 1930s distrusted them. They had moral, religious, and cultural committments that Mencken didn't respect. There certainly is a place in American politics for Mencken's cynicism and antinomianism, but making it the centerpiece of our thinking would be a mistake.
Surely the Washington and the Framers of the Constitution strongly disagreed with the Anti-Federalists. Lumping them together as one tradition is at best misleading and at worst false. George Washington and the other Framers believed in limited government, but I can't imagine them having much sympathy for those who openly proclaim themselves to be "anti-state". Limited government is not anarchy or statelessness, nor is conservatism.
Washington's Farewell Address does recommend non-intervention, limited government and general freedom of trade, but Washington was nowhere near as dogmatic as today's Rockwellites. I supect that if we'd had Rockwellites in Washington's day they'd slam him the way they attack other political leaders, siding with the Whisky Rebellion, rather than with the elected government.
McCarthy is right that National Review Conservatism is a post-WWII creation. It was developed to confront the realities of the Cold War. Whether those realities apply today is open to debate, but the origins of NR conservatism don't in themselves make it illegitimate. In retrospect, we might also see contemporary libertarianism more as a creation of our day, than as a true descendant of earlier philosophies.
McCarthy is intriguing when he depicts National Review conservatism as a synthesis of negative aspects of British and American conservatism. That idea is definitely worth considering, though whether what's combined is really the worst aspects of both cultures is debatable.
McCarthy is on much shakier ground when he casts Rockwellism as true conservatism. Rockwellites are far more amenable to anarchy and far more dismissive of government than any conservative can be. Go back to Edmund Burke and you see a conservative, a lover of liberty, and a man who, in his mature years, was no friend to anarchy or disorder.
There is something contrived and flimsy about the Rockwellites' mixture of anarchism or anarcho-capitalism with the traditional conceptions of religion, tradition and patriotism. It makes some people feel good, but the conflicts between anarchic libertarianism and traditional morality may be too strong to bridge.
McCarthy's charge that neocons "have no patriotism themselves; their loyalty is to an ideology" is a cheap shot worthy of Frum's own smears. It is true that the neocons do seem to have more committment to the idea of America than to the actual people who live here. This comes out in their enthusiasm for immigration. But isn't this preference for the ideal ideological country over the real one a problem for all ideologies? Don't we all have a problem coming to terms with a country that gave FDR and LBJ big majorities and put Clinton in the White House twice?
Military intervention overseas does sharpen the contrast between the ideal and real nation, but one can make the same criticism of the Rockwellites. Rothbard's enthusiasm for leftists who could defeat moderate conservatives and Rockwell's passion for secession and insurrection look to be examples of the same passion for the ideal over the real. Learning to love one's country both as it is and as one thinks it ought to be is more complicated than McCarthy lets on. Charges over who is patriotic and who isn't heat the blood but contribute little to resolving the questions at issue.
The genealogy McCarthy celebrates isn't the only possible one for an American conservatism. I certainly wouldn't say that the Federalists or Whigs are the true models for contemporary conservatism, but they certainly aren't to be dismissed out of hand. Their realism about human nature, public spiritedness, and committment to the national interest are also to be commended. They did much to curb the excesses of Jeffersonian and Jacksonian radicalism, not that those Jeffersonians and Jacksonians hesitated to use government power themselves when it was in their own best interests. One shouldn't ignore their contribution or demonize them.
It's always possible to grab onto a radical political tradition, and claim a true line of descent. Facing the troubles of the day and doing the right thing for the country and its people is harder. It doesn't provide such stark contrasts and clear lines. But it's worth more in the long run. I don't think National Review does that, at least not lately, but if they did, I wouldn't hesitate to support them over the Rockwellites.
Finally, "Wilsonian" is a word that has to be used with caution. Maybe it shouldn't be used at all. What does it refer to? Wilson's reliance on international rules and desire to keep us out of war? His subsequent endorsement of a crusading "war to end wars" or "war to make the world safe for Democracy"? The olive branch he extended to Germany? Or his willingness to starve that country into submission? His faith in international institutions and agreements? His intervention in Russia? His idealistic plan for peace? His unwillingness to compromise on matters of principle? Or the compromises, and betrayals that he eventually endorsed? It's not clear just who is Wilsonian and who isn't and what the opposite of "Wilsonian" is.