I was just thinking about how rare it is to see villains tried and executed for their crimes, even now that every other villain is a mass murderer. At best, you get mentions that they're sentenced to capital punishment or stories where, for once, they're innocent of the crime and the hero must prevent a miscarriage of justice.
So I figured I'd get the ball rolling on those rare cases in which bad guys actually go through some sort of legal process and are executed. These executions may not stick, mind you, but the state apparently tries once in awhile.
Bear in mind that I'm looking for legal executions specifically; legal deaths like the Crime-Master being shot by the police in a standoff or utterly illegitimate processes like HYDRA's show trials for failed operatives and the likes of Baron Strucker or the Neverland concentration camp really don't count in terms of what I'm asking about. I'd also like to avoid real people who appeared as villains in comics, though: Nazis and Mussolini and so forth shouldn't count here.
A popular variant is to make the execution the origin, rather than the finish, of a supervillain. Minor Midnight Sons enemy Short Circuit, for instance was empowered by the electric chair, and at least one of the Externals only discovered his immortality after a hanging. I'm not sure I'd count either one, since I'm more interested in stories that use legal execution as the villain's comeuppance. The dismantling of sentient robots and the like by government strikes me as a gray area, but as long as it's the result of some kind of real legal process and not a "heat of battle" situation, I figure they're close enough. Alas, the Vision's the only example I can think of here, and he's not really a villain getting comeuppance at the end of a story when it happens to him.
At Marvel, I honestly can't think of any! DC had a few I know of, mostly in the 1940s, but Marvel...not so much.