Art Carden is back to writing about, and linking to, interesting stuff on EconLog. Today's post contains a link to a debate between Professors Bryan Caplan and Jan Ting about whether war is ever justified. At one point, the latter claims that things would have gone worse in many, many places - and on net - throughout the world sans American intervention in World War II. Caplan asks how Ting could know this, and the answer is, of course, that he could not.
So the issue is whether intervention in the face of such radical ignorance could be advisable. Maybe one argument in favour of intervention is that the intervening country is relatively civilized and has an enviable standard of living and relatively good values. How could the intentions be anything but good? And maybe the threat of intervention keeps would-be fascists on better behaviour? We are still ignorance, but maybe these factors adjust the odds?
I think basic price theory argues for a "no" on the second question, and for a retort which spells "irrelevant" to the first one. Firstly, politicians competing for power within the foreign potential subject for intervention may well resist internal pressure (say, by interest groups or by people - Machiavelli argued that even despots must be responsive to "popular will"), but if this pressure is really for a significant change in policy, some other politician, less averse to the risk of foreign toppling, will win in a show-down with the incumbent.
Secondly, on the issue of whether the civilized status of the intervening armies' government matters, the intervening government is clearly more responsive to what is going on within it than elsewhere. And the point above applies here as well: within the foreign country, intervention in itself is not going to change anything as far as preferred policy goes. And as I have argued before, intervening powers may be unusually prone to failure with respect to setting up functioning institutions - which may well put the country back on its prior path anyway.
It seems to me that chances are that Caplan is right on this issue, but what other reasons are there to suppose that intervention might work?