The U.S. military hammered the daylights out of the Iraqi military, occupied the country, overthrew the government and put their leader in jail, all within a few months time. From a military perspective I'd say thats a pretty effective ass-kicking. The military did their job well.
Whether they should have been sent there in the first place is a different question though. You can argue that the evidence suggested they had weapons of mass destruction and a nuke program which justified our attack. But those things were not found so the question now is why are we still there?
We're still there because we're trying to stablize the country, so it doesn't descend into either anarchy, civil war, or theocratic totalitarianism. Whether we were right or not to go in the first place, we are now there to HELP the people of Iraq. Not to occupy, not to colonize, not to plunder. It gets my blood boiling, all of these so-called "insurgents," screwing over the future of the Iraqi people, preventing their ultimate peace, freedom, and prosperity. This has nothing to do with fighting against America. This has to do with being opposed to a free and democratic society. If they lay down their arms and accepted the new government, the Americans could withdraw, and Iraq could take its place among the democratic nations of the world.
We have the "insurgents" in Iraq, and the fact that among Arab League states, NOT ONE is a free democracy. WHAT DO THESE PEOPLE HAVE AGAINST FREEDOM???
Sorry, this whole thing makes me want to rant now and then.