Is Obama a War Criminal?

I'd like to post today some (hopefully) educational and philosophical thoughts on a major current event of considerable importance, on which every American should be well informed.

There has been much said of late (by both liberals and conservatives, even on the usually well-informed Daily Show) to the effect that Obama is a war criminal, because his aerial assault on Libya was unconstitutional and had no legal standing. Simply because he didn't get congressional permission first. This keeps getting repeated, by members of congress no less (who of all people ought to know better), even though it's obviously false to anyone actually aware of the law (much less its precedents: Reagan and Clinton both did exactly the same thing, multiple times, despite being icons of an "ideal president" for both the right and the left).