I suppose I would be remiss if I didn't at least link to the FP forum on realism and American foreign policy. The lead article is by Paul Wolfowitz, who conflates everything to the point where he can't figure who's the realist: himself or Brzezinski. Along the same lines: might Scowcroft be an idealogue? Wolfowitz is only half-serious, but that's the problem.
The response articles -- by Walt, Drezner, Rothkofp, and Clemens -- try to engage the issue constructively, but... this "debate" simply isn't interesting anymore. It seems like almost everyone (even Wolfowitz) agrees on the main points. I'll sum up as best as I can:
Realism has some fundamental insights, without which IR wouldn't be IR (and foreign policy wouldn't be foreign policy). One of these is that states can/should/must sometimes engage other states that they might not like very much. In other words, pragmatism is not optional. Of course, states would prefer to engage state that they like a bunch, so if Bad States turn into Good States, then all the better. On this, realists and neoconservatives mostly agree.
The difference? Realists do not think we should expend state power to make Bad States into Good States; neoconservatives do. I think it's fair to say that recent history has humbled both: liberal intervention worked pretty well in the Balkans in the 1990s, and non-intervention worked pretty poorly in Rwanda, Sudan, and elsewhere; intervention did not work well in Somalia or in Iraq, nor is it possible to intervene everywhere all the time even if we knew it would work.
Realists and neoconservatives have different expected utility functions for the use of force in achieving national objectives. All of their disagreements boil down to that, and the world provides enough contradictory evidence that both sides can think the data are on their side. Neither of them bother much with institutions, and when they talk about the "national interest" they discuss the political economy only obliquely and in passing. Nor do they (usually) bother identifying what the "national interest" is.
There. Now can we stop killing trees and wasting ink on this tired old argument? I think we've all got better things to do.