I recommend the Baltimore Sun's editorial today. I think it asks the right questions. (A second editorial says Rummy should step down.)
Excerpt, from the end:
It will take great patience and many years. It will be an American project, in fact if not in name. Americans should ask themselves if they are prepared for that effort. And if the answer is yes, the next question is: Can America win Iraqis to its side, given what has happened in the past year? Can the United States, in a word, succeed?
If the answer is no, it's better to figure that out sooner rather than later. Iraq has already complicated the struggle against violent Islamic extremism; there's no sense staying there if it only makes things worse. The question then is how to get out - and with as little additional damage as possible. http://www.baltimoresun.com/news/opinion/bal-ed.iraq09may09,0,5187737.story?coll=bal-opinion-headlines