First, the invasion of Iraq was not worth it because of the way it was done. The Bush Administration had flimsy evidence that Iraq had WMDs and acted upon that evidence like it couldn't have been wrong. Colin Powell went to the U.N. and (essentially) lied. People can twist it any way they like, but the information given to him was not entirely true. One of his aides considered it the lowest point in his life. Even then, the U.N. Security Council did not approve of a resolution to invade Iraq. Some could say that the U.N. was corrupt (and still is), but the U.N. is viewed as a legitimate source for action by a majority of the world; and that is what really counts. The Bush Administration took a handful of allies, basically said "screw you" to the U.N. and went into Iraq anyway. Now I know there are more details, facts, and other things that I am looking over, and I don't mean them to be less important. However, I am communicating that the Bush Administration use the massive amount of political power they received after 9/11 and basically shattered a careful international order past Presidents Clinton and his father created (see my previous blog post on the Gulf War, I go into this further). These flimsy claims decreased American legitimacy throughout the world. Our potential to do unilateral action when needed, with the international community accepting of it, has been almost shattered. The U.S. has begun to restore our image, but the damage has been done. I firmly believe, that in the modern world, multilateral-ism is key. Technology and the rise of the BRIC countries make the world a uni-multi polarity; the U.S. as the hedgemon, and strong regional actors. If one cannot see multilateral-ism is the function of the world as of now, they are going to have a hard time getting around. So no, Iraq was not worth it.
Another reason why Iraq was not worth it was the chaos it caused to the region. The balance of power in the region was no more balance. On one side, you have Iran gaining influence due to an Iraq no longer keeping it in check. Iraq may have not liked the west, but it certainly liked the west more than Iran. On the other hand, you have Turkey and Syria, who feared for their security due to a large American force so near. Wonder why Turkey did not let pass through in 2003? Because they were scared for their security (see pg 167, under "3."). Friends shouldn't scare other friends. The Kurds are clamoring for a new state, but no one in the region wants to give them one. Saudi Arabia has now stepped into Iraq's places as a rival to Iran, but isn't doing such a good job. The vacuum Iraq left its causing major change in the region. Aren't there enough problems already? So no, Iraq was not worth it.
In the aftermath of the invasion, there was massive amounts of blood shed. Iraq was on the brink of a religious civil war. Our troops were giving their lives for a war which was not necessary, nor was right to execute. 4,429 Americans gave their lives. Those brave soldiers shouldn't have died in Iraq, as the war was not a necessary war. It was a choice. A choice that ballooned the deficit and cost us billions. I firmly believe that. Deterrence and containment is a powerful thing. We did the same with the Soviets, why couldn't we with Iraq? So many brave Americans shouldn't have died. So no, Iraq was not worth it.