Islamic radicals are angry at the inability of their religion to achieve the same material goals as the infidels (non-Moslems). This cant be the fault of Islam, so it must be a conspiracy by the infidels. Therefore, the infidels must be destroyed, converted to Islam, or at least driven out of Moslem nations.
How do you fight failure? The major threats to world peace today are militant, violent movements trying to recover from their own failures by attacking, or threatening to attack, more successful nations. Nothing new in this. Throughout human history nations, or groups, have, when all else failed, attacked someone else. Real estate, revenge, loot, honor or an attempt to distract an unhappy population, are still the goals of this approach.
North Korea, the last hardcore communist state on the planet has the same basic attitude as the Islamic radicals. Communist China is still, for all its economic reform, a communist dictatorship. The Chinese communists are playing the nationalism angle big time in an attempt to distract the population from the continuing corruption and repression of communist rule. So war with the United States over Taiwan is pushed as more important than cleaning up the massive problems within the communist bureaucracy.
Failed states, like North Korea, or failed governments, like the Chinese communists, can at least be negotiated with. The Islamic militants are another matter. When youre on a mission from God, no compromise is possible. The communists are religious in the strength of their beliefs, but many of the Chinese and North Korean communists realize that their faith has failed them, and that they are simply trying to get out of bad situation without getting killed by the oppressed subjects. The rapid, and sometimes violent (for the leadership) collapse of European communist governments in 1989 scared the remaining communist dictators. They are now rather more desperate, but also more willing to negotiate with the capitalist nations they were once so sure of defeating.
The failure of the Islamic republics in Iran and Afghanistan have not dissuaded the Islamic radicals. Their faith is strong, and their belief, that their continued failure has nothing to do with their ideas or actions, remains. There was a time when millions of communists and fascists were just as firm in their beliefs. It took bloody wars, genocide and collapsed economies to change minds, although some true believers remain.
The Islamic terrorists are not nearly as dangerous as the communists or fascists were. While the Islamic radicals preach world conquest, they have neither the means nor the support to get as far as the nazis, communists or Japanese got in the 20th century. Taking over in Afghanistan and Iran was a dead end, not a springboard. The minority of Islamic radicals who still control Iran are trying to build nuclear weapons, and supporters of Islamic radicalism in Pakistan sold nuclear weapons technology to like minded parties. So terrorists with a nuclear weapon are a threat, but armies of Islamic radicals overrunning Western countries are not. In fact, the experience with Islamic radicals in the past few years has caused Moslem governments, who thought they could use Islamic radical groups, to reconsider their strategy, and are now fighting the radicals they once nurtured.
But theres no agreement on how much effort should go into dealing with the Islamic terrorists. Many Europeans thought it was a bit much invading Iraq. Earlier, Europeans and Americans also frequently disagreed on how to deal with the nazis, communists and other dangerous groups. Many Americans are appalled at how Europeans, who gave us communism, fascism, Hitler, Stalin, democide, concentration camps, gulags and state sponsored terrorism, have also turned out to be staunch defenders of guys like Saddam Hussein, or at least of keeping him in power. We now better understand why our European ancestors fled the place, and why our American ancestors were so determined to have nothing to do with Europeans.
The founding of the United States was something of a "great experiment" that was originally viewed with much horror, and amusement, by the 18th century autocrats of Europe. The French even supported this silly experiment, convinced that they could do so at the expense of their enemy, Britain. Some things never change. In the decades following that, the US was used as a model by democrats in Europe. But thousands of them were forced to flee for their lives in 1848, and their descendents are still bitter over the double dealing, and double talk, of those who run things back in the old country.
Americans find it pretty pathetic that Europeans are basically refusing to help democracy get established in Iraq, and will be "wrong" if it succeeds. But over here, this is seen as so typically European. While there is general agreement on dealing with Islamic terrorists as a police matter, few countries want to do anything more energetic. While awed by Americas power and initiative, most nations would prefer that the United States act like a slave, as well as a savior.