Revisited: Is there a statute of limitations on genocide?

Iraqi officials have confirmed that 300,000 people were slaughtered by the former rulers of Iraq. (For you aging hippies out there, that’s 75,000 times the number of students who died at Kent State.) Those numbers are sure to increase as other mass graves are found.
Sometime soon, I would like to explore the question of whether it is morally permissible for a state to intervene on behalf of grossly oppressed peoples. The last time we considered that question in December 2003, it was an occasion for a lot of hot-tempered dialogue, much of it my own.
Now, even the news media cannot paint the “insurgency” as a valiant resistance movement like they did with the murderer-thugs of the Viet Cong. The “insurgents” are simply criminals, and they speak for no one, save for a few marginal imams, washed-up Baathists, and several tribes who are used to holding the whip instead of working for the common good.
May their souls of these 300,000 find the peace they did not have in this life. May their murderers, and their successors who continue to kill and oppress the innocent, meet divine justice.