Unfortunately, terrorism has been going on in the world for as long as people have had reason to feel oppressed and the means to fight back in some way. The only difference today is that the world is a smaller place, the means to fight back have become more lethal, and terrorism is a global phenomenon. There is no way every potential threat can be countered, or every cause of discontent can be appeased, so people will continue to blow up things and there is nothing we can do to eradicate the world of that. You cannot police every inch of railroad track. You cannot protect every bus. You cannot control every suicide bomber. So with that said, are we going to be at "war" forever?
This is not to say that we shouldn't try to do something about it, but ours is an impatient society. We follow the issues on a day to day basis with the expectation that the events will soon come to some kind of resolution, that the game will end, the score will be tallied and someone will be declared a winner, so that we can then move on to the next issue/celebrity trial/scandal/reality TV show. The US public will become increasingly impatient with the situation in Iraq because it is going to go on, and on, and on, and soldiers are going to continue to be killed. Consider it is now the year 2024, do we really believe that the US will have stayed the course for 20 years? It is far more likely that come 2024 we will be reading history books that tell of how the US cut its losses after a few years and left the country to a shaky puppet regime that never had popular support. Following that departure, the history books of 2024 will go on to say that the regime was toppled by opposition, probably through a coup or uprising, and a few years later historians were comparing the region to that of the mid 20th century.
The Iraq mess will be remembered as being driven by a naive president who had the crazy idea that democratic way of life we enjoy today after decades of strife can be imposed on others in a mere few years, in a part of the world where the notion of everyone having a voice is not an idea that appeals to many people who can, and would, rather have the power to themselves.