So what was the governing constitution then?
If you are claiming Saddam broke the law, what law did he break?
These questions aren't important for dictators and tyrants, but the rule of law is supposed to be based on law, it's not about the result, it's all about the process.
If Saddam was brought to the Hague, he could be tried as a war criminal, and imprisoned, but in Iraq he has constitutional immunity, legally anyway, if this court doesn't recognize the law, then it's not a court of law, it's just a show trial, to be followed by victor's justice, not unlike a Roman Triumph.

This may not make a difference here in the US, but in the Middle East, it will be seen as the infidel nation, invading an arab homeland, and killing it's legitimate leader, denying him his legal rights, treating him and by implication all the people of the region as inferior subjects, not entitled to rights under the law.
Nice way to swell the recruitment lines for the big Jihad.

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"I think -- tide turning -- see, as I remember --I was raised in the desert, but tides kind of -- it's easy to see a tide turn -- did I say those words?"
-- George W. Bush, asked if the tide is turning in Iraq