It's possible that Rumsfeld simply attempted to resign yet again, and this time could not be convinced to stick around.
Why would he resign if he's doing a great job?
At the end of the day, it doesn't matter anymore. He's out.
What matters is coming up with a solution on the ground in Iraq. I don't care who has the solution I just want one that works. If Kofi effing Anan has a solution I would be interested to hear it. If Hillary has a solution that would work I don't mind listening to that either. If the French have a workable solution, I am all ears (assume 5 million 'F--k the French' and 'they will surrender' posts). But honestly, I don't care where the solution comes from, I just want one that works.