SPRINGFIELD, Ill. -- It's been a couple hours since long-time Chicago Mayor Richard M. Daley made a short, surprise announcement that he won't run for re-election next year. The story is getting picked up by news organizations all over the world, with a Washington epicenter that's abuzz over the possibility that this might be the opening White House Chief of Staff Rahm Emanuel has been waiting for. And still, we've yet to see a definitive ``why.''

Daley made his announcement in a Chicago news conference of less than five minutes today. The 68-year-old Daley, who has been in office since 1989, called it ``a personal decision'' that will allow him and his family to begin ``new phase of our lives,'' according to the Associated Press.

`` . . . It's time for me, it's time for Chicago, to move on.''

It was the usual vague political boilerplate, in other words. Though it wasn't specified as the reason, Daley's wife, Maggie, is being treated for breast cancer, a factor a lot of pundits are guessing is behind it, as Daley didn't appear to have any serious challengers to what would have been a 7th term.

In Washington, the speculation isn't ``why?'' but ``who's next?'' -- especially if that who is Emanuel, who was making noises not long ago about a mayoral run if Daley stepped down (which wasn't considered likely at the time). Here's Politico's take on it.

Daley is the son of the iconic late Mayor Richard J. Daley, widely considered the last of the big-city bosses.