Megan McArdle has a post up outlining the divide that developed among libertarians over foreign policy in the wake of the Iraq War:

A real non-interventionist has to accept that the United States should not have entered into World War II. Yes, Japan attacked us, but they did so because we were encroaching on their sphere of influence. Had we actually kept the navy within our territory, Japan would never have attacked, and we would never have entered World War II. 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. Moreover, since we’re not starting from some blank, non-interventionist slate now, this is not a compelling argument against entering into World War II at the time of World War II. Some libertarians do accept that (as does Pat Buchanan). Most, especially the more moderate breed nurtured post-Reagan, can’t accept a philosophy which means we should have allowed more millions to die in concentration camps, left the Russians and British to starve without lend-lease, etc. Their minds also turn to wondering how the American Revolution might have turned out had the French government adopted a similarly modest foreign policy. If you are not willing to posit that Americans should stay home even when millions are being senselessly slaughtered, then you end up in sticky pragmatic arguments about the possibilities of inherently untrustworthy state power to counteract even more noxious state power, and how much in the way of cost we can reasonably be expected to bear in order to advance liberty. I don’t think there’s an inherently libertarian answer to those questions. 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.

Keep in mind that when we use the word “intervention,” it can mean any number of things such as cutting off diplomatic relations, joining in international pressure directed at a regime that is repressing its citizens, leading or joining in an economic boycott against that regime, supporting an internal opposition aimed at overthrowing that regime, all the way up to direct military action. This is important because the answer to the “should we intervene” question depends, in no small degree, on the type of intervention we’re talking about.

The question that McArdle’s post raises, of course, is when, if ever, the fact that a state like Iraq is violating the rights of its citizens justifies intervention in their internal affairs. If the answer is that the existence of a repressive regime is per se justification for intervention, then you’ve basically adopted a neo-conservative/Wilsonian idea of foreign policy, with all the attendant disasters that come from it. And here I disagree with McArdle in one respect — the negative impact that Wilsonian interventionism had on World War I, or more specifically on the peace that followed, clearly did have an influence on the events that led to another World War less than 30 years later. If the United States had stayed out of World War I and not intervened in the peace negotiations in Versailles that ended the war, then the treaty that ended the Great War would have, most likely, been far less punitive toward Germany, and that alone could have prevented the rise of Naziism.

If the answer to McArdle’s question is that intervention is never justified unless the United States is directly threatened, and even sometimes not even in that case, then you’ve basically adopted the position of the isolationists prior to World War II, who would have apparently been okay with Europe falling under Nazi rule and every Jew being sent to their death.

I don’t think that there’s an easy answer to this question and, in part, it depends on the kind of intervention that is being talked about.

Absent a direct threat to the United States or its interests, military action against, say, Burma, would not be justified; but that doesn’t mean that it would be impermissible under libertarian principles for the United States to suspend diplomatic relations with the Burmese junta, or to impose economic sanctions against the country in retaliation for their repression of the pro-democracy movement. Similarly, though less convincingly, the no-fly zones that were imposed in the northern and southern Iraq from the end of the First Gulf War until the U.S. invasion in March 2003 were arguably justifiable as means to protect the Kurdish and Shiite minorities that had been terrorized by Saddam Hussein’s forces.

Since there are gradations of “intervention”, many of which fall short of direct or indirect military action, I don’t think it makes sense to say that “intervention” can be judged by a specific set of principles or that “intervention” is always per se unjustified. Again, if you make the former argument they you are essentially saying that the United States should have stood by and done nothing in the years prior to World War II while the Nazis rolled over Europe — because Lend-Lease would have been a violation of a policy of strict non-interventionism.

I don’t know about you, but that’s not an outcome that I could accept.