You know it really amuses me both with saddam and gaddafi how people wonder why they were invaded. Excuse the language but they fucked around and found out.
If someone threatens to kill you, do you say to yourself "nah, he won't actually do it?" Or remove them from a position of threar against you like having them jailed?
Well between nations, it isn't exactly unprecedented to invade a country and remove from power leaders that publicly and vocally threaten to cause you harm. Bush lied about wmds because of oil but the reality is, if saddam was friendly to the US or even indifferent he would have been left alone.
Now vietnam and korea, I can see how you can argue the US had no business being involved but the moment saddam, thr taliban and gaddafi threatened the US, the US was involved. Pre-emptivr strike is term they used to justify these invasions. You don't have to agree with the concept to appreciate the fact that the US is one of many countries in a long line of countries that invade in response to a threat made by other countries.