fighting terrorism is like fighting the "war on drugs." there is no one nation that can accept all the blame, so for us to declare war on an entire country because 1/10,000 of the population had a part in what happened to our country is not exactly the best way to go about it. In fact, all it really does is waste insane amounts of money and the lives of our soldiers.
If you want an effective way to handle it, do what spain does. they use intelligence (well, I guess we can't use this because our intelligence agency is completely inept) and once they find out enough info and positions of terrorists, they use police to aprehend them.
that is never going to happen in this country though because it would be as profitable for the bureaucrats