Ann Wright, one of the few to resign before the Bombing of Baghdad, tells her story in an interview at www.tomdispatch.com , well worth reading.
"Tragically, Colin Powell, who was trying to counsel Donald Rumsfeld behind the scenes that there weren't enough troops in Iraq, never stood up to say, "Hold it, guys, I'll resign if we don't get this under control so that logical functions go in logical organizations and you, the Defense Department, don't do post-combat civil reconstruction stuff. That's ours."
He just didn't do it. To me, he was more loyal to the Bush family than he was to the country. His resignation was possibly the one thing that could have deterred the war. Then the people of America would really have looked closely at what was going on.
But tragically he decided loyalty to the administration was more valuable than loyalty to the country. I mean, it breaks my heart to say that, but it's what really happened."