Mark Warner won't run for President:

So about a month ago, I told my family and people who know me best that I would make a final decision after Columbus Day weekend, which I was spending with my family. After 67 trips to 28 states and five foreign countries, I have made that decision.

I have decided not to run for President.

This past weekend, my family and I went to Connecticut to celebrate my Dad's 81st birthday, and then we took my oldest daughter Madison to start looking at colleges.

I know these moments are never going to come again. This weekend made clear what I'd been thinking about for many weeks--that while politically this appears to be the right time for me to take the plunge--at this point, I want to have a real life.

And while the chance may never come again, I shouldn't move forward unless I'm willing to put everything else in my life on the back burner.

This has been a difficult decision, but for me, it's the right decision.

This is shocking news. Unlike Kos, however, I'm not totally convinced by the explanation. Maybe it was a family decision, maybe it was something else. But when I saw Warner in Chicago back in April it seemed clear he was totally committed to runnning, and he hasn't offered the slightest hint in the seven months since then to indicate otherwise. He's gotten great press and been very well received by Democrats all across the country, so I find it hard to believe he'd just up and call it quits at this moment unless there is more to the story.