If boots do hit the ground in a war, Europeans believe it will be because they have failed to prevent it. They prefer endless diplomacy to once-in-a-while war. Europe's reluctance to go to war frustrates some Americans. I believe their relative pacifism is because Europeans know the reality of war, while most Americans do not. Of course, if you have a loved one who has fought or died in Iraq, Afghanistan, or Vietnam, you know what a war is. But as a society, the US can't remember actually hosting a war.