The Iraq war, or the second gulf war. It was based on a policy of prevention, when in fact we instead got a new theatre in the great war on terror.
It's pivotal purpose was to disarm Saddam's weapons of mass destruction, nuclear, chemical, and biological. The nuclear part of it was based on, what we thought, strong intelligence. CIA, MI6, Russian, Jordan, Egypt, said they were in there. All these repots coming in, they got them, they got them! The rest of the world said we were nuts, but there was more to it, more pieces of the puzzle that made this threat more buyable than just intelligence.....
As for the biological and chemical weapons, we have found some of those, but not what he had. And we know he had them, because he used them on the kurds before, and Iran. They are misssing, and many people suspect they are along a neighboring border, or in a country. Primarily Syria.
Another reason was that Iraq was suspected of harboring terrorist cells, and this has come to be true. Parts of Hezbolla and HAMAS were in baghdad, but more importaintly a direct spawn of Al Queda had a strong presence. It is lead by a man of the name Al Zarqawi.
Zarqawi was in Afganistan for two years, helped train Al Queda members, and actively fought in the war in Afganistan. He was injured, he went through Iran to Iraq, fleeing to Iraq, he knew they would take care of him. And they did. He then built his "army" in Iraq, largely during the time period the US was "dilly daddling" with the UN, this extra time let Zarqawi fill up his ranks. When the US invaded, they went "underground" and fights the US to this day.
http://www.globalsecurity.org/military/world/para/zarqawi.htm
And lastly, the war was also to remove the Baathist regime from power, this was largely based on Saddam's defiance of UN resolutions. And uh, I could mention all the horrible things his regime has done, but do I need to bother?
These are the main reasons for going to war, and now, let me say something about the current situation.
The Bush administration, by all factual accounts, had every right to overthrow the Baathist regime. But was it done correctly? Taking a look at Iraq, it is easy to say no. I think this is somewhat correct, for instance, it seems Donald Rumsfeld didn't have a clue about what would happen in Iraq, it was like a surprise that the insurgencey happened. Considering his poesition, that is a fatal error. They didn't plan well for the aftermath.
So the primary reason we came to Iraq, wasn't fullfilled. But another one was: Terrorism
The great struggle with militant Islam is now taking place in Iraq- but is this a blessing or a curse? Iraq now symbols which way Islam will fall, will it be sucked up by Islamic fanatics? Or will it embrace democracy, and lead Islam into a world of modernization and prosperity?
While America certianly has the power to win a military war, the political war will remain ever so complex. But most importaintly, like the South Vietnamese, it will be solely the Iraqi's decision whether or not we win. They will either fuel the evil, or repel it.
If we win this, it will be an immense victory, if we fail, then....... god help us all.