Is War ever Worth it?

In American Studies class, we started a unit on war, and one of the leading questions is if it is ever worth the consequences. At first, the answer may seem like an obvious yes or no, but every story has more than one side, and I decided to look at war from both. I took a more recent war, the Iraq war.
When America was pondering the decision of whether or not to go to war, there were many pro-war and many as well who were anti-war. The evidence in favor of going to war was that The United States had the authority to use force against Iraq, and they had the capability to make weapons of mass destruction. Saddam had a terrible human rights record, and deserved to be punished for all the misery he'd caused, and Democracy could have stood as an example to surrounding countries. Also, the cost of containment would actually be higher than war itself. All this, as well as the fact that Bush and United States' role as the fixer were at stake, was good reason to go to war.
While this may make the answer seem obvious, one has to take a look at the other side. The evidence against going to war with Iraq included the fact that there was no hard evidence of weapons of mass destruction, as well as all the innocent civilians and soldiers who would be killed. There was possibility that weapons would be launched at alli countries, and also that there could be vengeful attacks from terrorist groups.
While all this evidence is very persuasive, both sides just seems to make it confusing. Maybe the only thing there is to learn from this, is that when looking at war, there is never an obvious answer to whether or not it's worth it.