And no, I’m not convinced by arguments that our intervention in WWI brought about WWII; our role, other than urging France and Britain to mitigate their vengeance, was fairly minor. ~Megan McArdle

It was a minor role, if deciding the outcome of the war was minor.  Here’s the thing: intervening in WWI was fundamentally a terrible mistake because it was not America’s fight and our involvement served no national interest.  It was not wrong primarily because it contributed directly to the creation of the awful post-war settlement and the consequences of that settlement, though it did do that by providing the Allies with the needed manpower to end the war on terms unfavourable to the Central Powers, but because we had no business being in that war.  The consequences of our entry into WWI being what they were, you would have thought that later administrations would not make the same mistakes (no luck there), but it was possible to know that intervention in WWI was wrong in 1917 (and the vast majority of Americans opposed entering the war).  With WWII, once the Japanese attacked and Germany declared war staying out of the war was no longer possible (obviously), which is why Roosevelt’s earlier policies that drew us into the war are so damning of his administration.  As in WWI, the wars in Asia and Europe were not our fights, but Washington saw to it that they became so. 

McArdle continues later:

Libertarians should be inherently more suspicious of the American government’s ability to make things better than other groups–but by the same token, it seems to me that they should be inherently more suspicious of repulsive states such as the dictatorship of Saddam Hussein.

All right, be suspicious.  How being more suspicious of Saddam Hussein would lead someone–allegedly on the basis of libertarian principles–to endorse a war of aggression is simply beyond me.  There’s suspicion, and then there’s irrational paranoia.  The idea that Hussein’s regime plausibly posed a threat to this country was fantastical.  The fact that a lot of people shared this fantasy did not make it any more reasonable.  In any case, how do you go from being suspicious of a regime to advocating aggression?  Isn’t the principle of non-aggression supposed to be at the core of libertarianism?  Or has that, too, now ceased to be trendy?