Irrespective of the numerous political reasons why Saddam needed to be killed, I think that trying to argue that his execution is unwarranted as a matter of Catholic teaching is exceedingly wrong-headed. As long as he was alive, he continued to serve as an active and willing rallying point for his followers that sought to restore him to power. That was the whole goal of al-Awda (the Return, i.e. the Return of Saddam), which back in 2003 was one of the leading Baathist groups in the insurgency. And while they have since been replaced by al-Qaeda in Iraq, they are still active and still killing people today. So even without taking into account his enormous crimes against the people of Iraq and their neighbors, I think you can make a fairly compelling case for executing Saddam on grounds of the public good. Your average criminal is not going to have followers carrying out violence with the goal of securing his release as long as he was imprisoned, whereas Saddam's were. Under the circumstances, I'm not seeing a problem here. The idea that to execute someone is to deny the efficacy of God to carry out justice is both a red herring and very bad theology - taken to its logical conclusion, that would mean that we shouldn't have any laws or punishments whatsoever. As I believe it says in the Catechism, God has chosen not exercise all sovereignty Himself.
Also, this has been bugging me for some time but Mark really needs to cool his inner integralist the next time he denounces conservative blogosphere for not following the teachings of the Catholic Church. As he seems to recognize whenever he is dealing with, say, Jonah Goldberg (unless he's also be subject to anathema sit), a lot of conservatives aren't Catholics, so it isn't surprising that they aren't going to be in synch with the Church when it comes to issues of morality. A lot of them probably don't follow the Church's teaching on Petrine primacy or contraception either. Why we should expect otherwise when we believe that the Church is the summit of truth (thereby implying that others would have less access to it than we do) is beyond me.
Now that all said, the manner in which Saddam's execution took place was extremely bad politically. Here's why: beyond angering all the usual suspects in the West (of whom Mark is now unfortunately among, given his creeping paleoconservatism), by allowing Muqtada al-Sadr's thugs (and al-Sadr himself?) to oversee the execution, al-Sadr and not the Iraqi government are going to get credit for killing Saddam Hussein, giving him even further prestige as he seeks to position himself in a position of leadership in Iraq.
I really can't add much to Tom Connelly's response (quoting David Frum) to Mark's idiotic remarks about neocons now being critical of President Bush:
Where did this idea come from that either you must support and applaud everything the administration has done in Iraq - or else you must turn your back on the whole thing? Intense debate over strategy and tactics is exactly what you would expect in a democracy at war. Those who support a war's aims do not always or even usually support every element of a war's execution.
Of course, if Mark care enough to pay attention to what the neocons were saying, he might recognize that Bill Kristol and the Weekly Standard have been calling for more troops and Rumsfeld's removal since the summer of 2004. And then there is the issue (unanswered in the combox) as to why neocons becoming critical of the administration's conduct of the war is any different from Mark. The answer: because the neocons still want to win in Iraq, whereas Mark appears to have more or less given up on victory in the war on terrorism as a practical matter until Western culture readjusts itself to a point he regards as healthy. Thank God his attitude was not prevalent in the 1940s, when all manner of religious, racial, and class bigotry every bit as inimical to Catholic values predominated American society.
As for this, Mark makes a false conflation between prisoner abuse and torture (there is a difference between the former and the latter), just as he conflates disagreement with him and his bad arguments on Catholic teaching to a desire to condone torture. Until he can wrap these differences around his head (an event I expect will result in a Nomad-like collapse of his internal reasoning), he isn't going to be able to do more than demagogue when it comes to this issue ... which has pretty much been what he's been doing since it became clear that he isn't willing to argue substantively because he believes that anyone who disagrees with him (and isn't a prominent Catholic apologist) is motivated only by politics.