According to Robert Kagan and his new book (reference is in the bottom of the article) Europeans and Americans share a common view of the world but they have differences about a morality of power. Europeans are turning away from power to a "self-contained world of laws, rules and cooperation". The United States on the other hand is exercising the power, it feels that they have a strength and a moral mission to improve the world on their own rules. It looks as like Europeans and Americans traded the places. In the past the USA was far from interfering in international affairs of other countries, there was quite a skepticism to enter the WW II before Pearl Harbor even when Nazi occupied almost all Europe.
We need to remember that Europeans know what war is from their own experience. The last two world wars of the XX century took place in Europe. Americans did not experience any war on their territories since Civil War. So, for them war is something abstractional, untouchable, like from the computer game, except these who served in WW II, Vietnam. Probably also New Yorkers have some feeling what war is after destruction of two World Trade Towers.
After the WW II Western Europe kept its important strategic place between the communism and the democratic capitalism. But economically many countries suffer heavy damage not only because of war but also because they lost the rests of their colonies and their influence in the world. The center of science moved to the USA as well as a center of the artistic and political life.
Western Europe concentrated on building its economy and its democracy and a system of social protection for its citizens but relied on the USA in case of military danger. The main task - was to build prosperity for the citizens. Too many expenses for military could ruin this system. Now, Europe builds its common market, common currency through the European Union. It emphasizes the common economy, currency, prosperity of citizens rather than the strength by building only European defense system (although there is some talk about it also).
So, Europe built through the years only fractional system of defense and does not anticipate to take part in any military conflict beyond their boarders. Also European citizens do not feel that it is appropriate to send their military to solve problems somewhere to the distant countries. They rely on NATO and the USA for their defense. They also question any use of the force, which seem to be excessive.
Why some countries are opposing the USA more than others?
France historically was always very critical towards the USA. One of the reasons, France lost its significance in the world on expense of the USA. Still until the end of XIX century Paris was dictating the fashion in the world, it was a center of the artistic life and the new political ideas. French language was the most common used language in the world. It all changed. I do not question the sincerity of French citizens in their critique towards Iraqi's war, but the truth is that French leaders were almost always opposing Americans policy. France did not want American planes to enter French airspace during the Gulf War. Jean-Pierre Chevenement was "Ministre de la Defense" before and during the first few days of the Gulf War in 1991. He was very vocal in his opposition to the war. He resigned on January 29, 1991. After his resignation president Mitterrand decided otherwise and finally the French airspace was open. In 1995 present French president, Jacques Chirac provoked quite many protests by unleashing his nuclear weapons testing program. So, French policy in general is not really so peace-oriented as they try to present themselves to the world right now.
As for Germany, I believe that German politicians are much more sincere than the leaders of many other countries. Germany's foreign policy is open to the world problems. After the WW II Germany went through the time of the moral retrospection. The government wanted to repair any suffering done to the rest of the Europe. They allowed massive immigration of foreigners (political refugees, gastarbeiters) and so called German resettlers (aussiedlers) into their own territory. Germany wanted to change its image from an aggressor responsible for two world wars to a peace loving country. They succeeded to a large extend. Germany and Germans improved their image in Europe dramatically because of its policy, hard work, good economy (now a bit sluggish after incorporating the Eastern Germany). Germany is also praised because of its very friendly and cooperative politics towards Eastern European countries. So, it sounds very authentic when Joschka Fischer, foreign minister of Germany, replied to American demand on cooperation in case of Iraq, "how can I convince my people when I am not convinced"; "Germany fought two wars from wrong reasons already, so we have to be much more skeptical". As Die Zeit has declared (14.2.2002), "a military attack against Iraq would be the wrong war, for the wrong reasons, at the wrong time."
The book below was an object of several commentaries in the press. The author was invited to many political discussions. It is really interesting! Of Paradise and Power: America Vs. Europe in the New World Order by Robert Kagan.