What was saddam's act of terror again?
What relevance does that question have?
You lefties persist in thinking of the US military as a some sort of glorified international police force whose purpose is to punish wrong-doers around the world. This is why you're so confused about the disparate treatment of Gadaffi vs Saddam. You guys have got to quit conflating military matters and judicial matters, before it gets more of us killed.
The purpose of the US military (and of foreign policy generally) is to secure the interests of the United States. The purpose is NOT, I repeat
NOT, to serve as some sort of justice-meting entity that equally and fairly prosecutes all wrong-doers. Think of the military in the right terms and you begin to understand why the US military was used in Iraq, and how that use was effective against Gaddafi, even thought the two men weren't treated the same way.
Saddam provided headquarters, operating and training bases for terrorist organizations willing to attack his adversaries such as Iran, Turkey, and Israel. He paid bounties to the families of suicide bombers who attacked Israel. He used chemical weapons on innocent civilians at least once, possible multiple times. He persistently attacked American and British forces enforcing the Gulf War I cease fire agreement. He attempted to assassinate a former US President. He was apparently pursuing more WMD. He was willing to brutally murder, rape, torture, and/or imprison people on a whim. Innocent life held no value to him.
Now, recall that the purpose of the US military is to protect the interests of the United States. We knew that Saddam had WMD. We knew that he was willing to use WMD against innocent people. We knew he was willing to use terrorists as proxies to attack his adversaries, and we knew he considered the US one of his adversaries to be attacked at any opportunity. Add it all up and you see that Saddam's government was a serious threat to the United States that needed to be effectively countered. Couple that with the strategic value of an allied, democratic nation in the heart of the Middle East, and the regime change effort in Iraq was a no-brainer.