would say that the same holds true for the death penalty. If killing is wrong, then executions are wrong. However, the immorality of executions may be the cost we must pay for a civil society.
War with Iraq would also be immoral. One could say that it would also be immoral for the United States, with it's resources, to allow Saddam to stay in power because he posses are real threat to his people and his neighbors. But even if this is true, it would not make war moral. This is where the phase "necessary evil" comes from.
These are are well reasoned points, and well written. The first distinction you make is between necessary and moral; John Paul II makes this distinction in 1995's Evangelium Vitae, teaching against the death penalty. To kill two birds with one stone here, I am against the death penalty (not a popular FR position, to say the least); anyway, JPII instructs that it is not necessary to implement the death penalty in civilized society any longer. Law enforcement techniques and educational levels have advanced to the point that we no longer have to make graphic examples out of criminals who break the law (beheading, etc) to discourage crime. In this way progress pinches off necessity; killing is never good.
A second reason that I'm against the death penalty is that it makes it much easier to make the pro-life case. For instance, if I am attempting to argue that rape and incest are not mitigating circumstances in regards to abortion, effectively I am arguing that the principle of life trumps whatever personal revulsion I may feel about how that life was created. If I argue that, it is difficult to turn around and argue that certain heinous crimes are only avenged by the death penalty. Such reasoning is similarly man-centered as the argument for rape and incest exceptions regarding abortion. I believe in a G-d-centered standard.
Finally, regarding Iraq, I'm for it, for what you would consider both moral and necessary reasons. It is moral to prevent further slaughter of innocent Iraqis (a Wilsonian goal), the seizure of weapons of mass destruction (a Jacksonian self-interest goal), and finally (as a bonus) the Hamiltonian goal of cheap oil. I would go morals/national defense/economic interest in that descending order, but really the stars all align on this one. Yes, people will die, and that's awful, but the alternative is worse. I know that skirts close to Peter Singer-like utilitarianism on life issues, but "we all fall short of the glory of G-d", as Paul instructs. I suppose in the end we ask forgiveness.
BTW, a great piece of literature for clarifying the issues at hand here is the Mytilene debate. The question at hand is whether Athens should crush the entire rebellious state of Mytilene (which had previously allied with and owed its prosperity to Athens), and kill all the men of the state, or kill only the rebellious leaders and spare all others. At first, the argument from Justice--represented by the orator Cleon--prevails and Mytilene is doomed. Then, Mytilene is defended from 'necessity' by the orator Diodotus, whose argument eventually carries the day. Interestingly, the moral conclusion (only punishing the organizers of the revolt and not destroying Mytilene) is made by appealing to pragmatic political concerns and self-interest, not morals.
Cheers...