Saddam Hussein wasn't the nicest guy in the world
Pardon? Not the nicest guy in the world? A slight understatement there don't you think?
When he took power he had 22 members of the Ba'ath Party executed (by the former party members) along with hundreds more members of his own party over the years that followed.
Then there was the Al-Anfal Campaign. This was the genocide of the Kurdish people in Iraq, which included a chemical weapons attack on the town of Halabja in 1988. Here the Iraqi Air Force deployed a combination of Mustard Gas (the same weapon used in WW1) as well as Nerve Agents like Sarin and VX. Somewhere between 3,200 and 5,000 were killed along with around 10,000 injured in the attack. As for the Kurdish population at large the Al-Anfal Campaign killed an estimated 182,000 civilians (though they range all the way up to 300,000).
There is also the Dujail massacre (the event that he was hanged for). A failed assassination attempt led to the deaths of 148 people and many more were probably beaten and tortured.
The Iran-Iraq war which ran between 1980 and 1988. Here again chemical weapons were used against Iranian soldiers (the effects of which are still being felt, no doubt, by the survivors). Whilst the conflict at large led to the deaths of in excess of a million Iraqi and Iranian soldiers (and set both nations economic and social development back by a decade or more).
There are various estimates for how many people Saddam's regime killed. The New York Times obituary estimated it at one million (excluding the Iran-Iraq war) and there are other estimates that whilst slightly lower are still in excess of 500,000 deaths (again excluding the million killed in the Iran-Iraq war).
So yeah not the nicest guy in the world.
To be honest, whatever the reasons for invading Iraq in 2003, I don't think that it was a bad thing that man such as Saddam Hussein was removed from power (though I'd have rather seen him tried by the International Criminal Court). Indeed to my mind the biggest failing of all wasn't going to war on faulty information and more that we didn't have a workable plan for the aftermath of removing the existing government (and indeed removing the entire machinery of government as well).