This is my take on it:
There is only so far you can go in inflicting just punishment upon an evil person. Yet how evil is someone who has murdered one person in cold blood, compared to someone who is guilty of genocide?
The crime of murder is heinous in itself, but does the fact that someone may be responsible for millions of deaths make the crime of multiple murder a million times worse than the person who kills only once?
In 1966, a spate of child-killings occurred in the United Kingdom, they were commited by Ian Brady and Myra Hindley. http://www.crimelibrary.com/serial_killers/predators/moors/myra_2.html?sect=2
Brady finished up in a prison mental hospital. But Hindley was as sane as anyone can be, and remained in a conventional prison. Once she had served a substantial part of her sentence, her case automatically came up for review. She was denied parole.
Again and again she applied for parole but was denied it. Hindley was forced to remain in prison and reflect on the crimes she had committed. Eventually she admitted to having commited other child murders in an attempt to wipe her slate clean.
Although this relieved the suffering of parents who had never been able to find out what had happened to their disappeared children, it still took around 20 years for Hindley to admit to the extra killings. If she had truly felt some remorse she would have admitted to these killings to relieve the suffering of those parents much sooner.
The fact is, that it was the anguish of having to face the rest of her life in prison that prompted Hindley to come clean. That anguish as she reflected on her actions was a continuous part of her life, all day, every day. If we?d executed her, then that anguish would have lasted for just a minute or so after the trap door had swung open.
Back to Saddam: I doubt he will ever have one moment of remorse if he?s found guilty of genocide and other associated crimes.
I do believe though, that he will still reflect on those crimes and wonder if it had all been worth it. His victims families will know that he?s reflecting too, which will afford a modicum of comfort to them.
For anyone to legally kill anyone, does, IMHO, simply re-inforce the belief that violence against a person is the ultimate answer. Killing killers might be appealing to those who are outraged by them, but that just makes us killers ourselves.
We need to make these people who are guilty of heinous crimes reflect on their actions for the rest of their lives. If we can do this without mimicking their crimes by executing them, then we remain unbesmirched by their evil.