“I tried to avoid this war,” Powell said at the Aspen Ideas Festival in Colorado. “I took him through the consequences of going into an Arab country and becoming the occupiers.”
In that light, Powell should have resigned rather than continuing as Secretary of State. Powell doesn't say whether he spoke with Bush before or after his own dramatic UN presentation that turned the American public in favor of invasion. If he spoke with Bush before the UN presentation, Powell bears enormous responsibility for justifying an invasion he didn't believe in. In my opinion, that would make Powell just as culpable for the war as George Bush, Dick Cheney, or Paul Wolfowitz. In fact, one could argue that Powell would have had a greater culpability because lack of public support might have forced Bush and Cheney to call off their invasion.
Even if Powell talked with Bush after his UN presentation, he still should have resigned. A resignation would have stiffened the backs of the Democrats (who really needed it), given legitimacy to the anti-war movement, and perhaps pushed a couple per cent of the vote to John Kerry in 2004. That's all speculative, but Powell could have given alternative scenarios a much better chance is he had left the Bush administration in protest.
By the way, Powell isn't helping his reputation or legacy through these revelations. Just thinking about it makes me nauseous.