The invasion was not unilateral anymore than the invasion to retake Kuwait in 1991 was. Invasion was indeed the only option in regards to removing Saddam from power. A simple understanding of Saddam's military capabilities prior to the start of the war as well as the strength of his security services proves that fact, as does the numerous failed attempts made by many over Saddam's 25 year reign over Iraq. The only thing that could remove Saddam from power was a military invasion, and that successfully happened in 2003.
There are few if any countries on the planet that have experienced more war since 1945 than Israel. If your looking for the attitudes towards military intervention from a country that has more experience than most when it comes to civilian and military experience in war, you don't need to look any further than Israel. The population there strongly supports US military intervention in most places around the world. They understand the mistakes of World War II, and that while being reluctant to intervene because of the cost is understandable, what is often not understood is that the cost of NOT intervening can be far greater.
As for Europe, you find the strongest support for US military intervention among those that live in Eastern Europe as opposed to Western Europe. Some of the largest contributions to the coalition in Iraq come from Eastern Europe. Thousand of Polish and Ukrainian troops have served in the "unilateral war" in Iraq. Iraq's military today is being equipped with Soviet made equipment donated by Eastern European countries.
The countries most strongly opposed to military intervention in Europe tend to be the countries that have not been heavily involved in war since 1945 if at all. Since 1945, how many Western European countries have lost the number of people that the United States has in war since 1945. The United States has lost over 120,000 people killed and over 600,000 people wounded since the end of 1945. Germany has lost a few dozen people since 1945. Sweden, Norway, Italy, Spain, Portugal, France, and for that matter, all of Europe with the exception of the former Soviet Union and former Yugoslavia losses in war since 1945 would not even amount to 5% of what the United States has lost since then.
The only place in Europe that has actually experienced war on its territory on a large scale since 1945 is Bosnia. What most people in Bosnia remember in regards to the question of military intervention is that everyone waited to intervene in their case. The same arguements about not "rushing to war", and the fact that the costs would be to great and would make things worse, were used to prevent military intervention in Bosnia in the 1990s. The United States and the rest of NATO sat and did nothing significant for years.
Even the members of U2 knew the arguements against military intervention in this case were bullshit and were strong supporters of early military intervention to end the conflict as evidence in Bill Flanagans book, "Until The End Of The World".
While many Europeans and Americans developed "alternatives to military action" and attempted to implement them, over 300,000 Bosnians were massacred, this in a country of only 4 million people. When military intervention finally came, the war was successfully ended in a only a few weeks. But it was several years and 300,000 dead civilians to late for many Bosnians. Most Bosnians would say that "half measures" and ignoring the situation is not going to improve things or in fact prevent what you most fear. Being reluctant to intervene with the military can have enormous costs!
World War II could have been prevented if the Allies had simply enforced the treaty agreements that had ended World War I. Instead, out of their understandable fear of starting a war after the destruction of World War I, they let Germany build up its mililtary forces and annex territory around it, all in violation of the treaty agreement designed to keep the peace. Germany could have been stopped in the early to mid-1930s, but the reluctance by other European nations to take any military action allowed Germany to rebuild itself, and wage the most destructive war in human history. The price of waiting to intervene with the military in this case, was over 40 million dead in Europe alone and potentially Nazi domination of the entire planet. People don't understand how close the Allies came to losing everything.
The United States and several of its Allies learned from the tragedy of World War II, and from then on began to maintain large military forces in peacetime, which successfully prevented World War III, kept much of the world free of Soviet domination, and won the Cold War.
Sometimes, early military intervention is a necessity. Certainly, there are sometimes better methods of action than military intervention in some cases, and given the situation, these methods should be allowed to work and military action put off or not entered into at all. What option is chosen will always been dependent on the specific situation. There is not a standard one size fits all rule in regards to when and where the United States should intervene around the world. It will always be dependent upon multiple factors to include the chances of non-military options to successfully resolve the situation, as well as the cost of military intervention, the cost of NOT engaging in a military intervention etc. To many people ignore the fact that not intervening with the military can have have enormous cost as well. Sometimes, early military intervention is required to prevent enormous loss of life or serious risk to security.
The military intervention in Iraq came after 12 years of sanctions, weapons embargo's, inspections, no fly zones, large military deployments and heavy bombing. It was anything but a "rush to war". But if one ignores the history of the situation prior to Bush coming to office, that might not be clear.
