My theory is that America has a totally different point of view on war compared to the Europeans. Much of Europe was destroyed in WW2...America suffered only two attacks on its home soil(I'm not counting the bomb laden balloons that the Japanese launched into the jet stream in the forlorn hope of hitting something in America). There was Pearl Harbour of course and also the Japanese occupation of a couple of the Aluetian Islands (I suspect most Americans would struggle to find the Aluetians on a map).

For Europeans war is something that should be avoided at all costs, there are still enough people around who lived through the war and/or the years afterwards for the memories to still be strong. America just doesn't have that experience.

Likewise, while the horrrible effects of poison gas attacks haunted people in Europe for years after the Great War...and the institutional memory has remained, few American soldiers where ever targetted by it and the proportion of the population that was involved in the war was much smaller in the US.

They lack the frame of reference to understand that war and chemical weapons are bad. When you combine this with an elite that is avaricious and drunk on power and a President who makes foreign policy at about the level of an 8 year old its bad news for Iraq...and whichever country or countries they decide to invade next.