The vote's still coming in--county results here. She's up 53-44 with two-thirds in. They haven't called it yet because it appears a lot (perhaps most) of the votes still out are in Jackson County (Kansas City), St. Louis City, and St. Louis County, where Obama is disproportionately strong. It's going to be close, but my back-of-the-envelope calculations look like he might come up just short. It would be a nice win for Hillary, but still an impressive showing in a state where just a week ago he looked to have no shot.
Interestingly, whereas Obama's doing better in Republican states nationally, in Missouri it's reversed: she's winning in the rural areas, he in the Democratic cities. (Probably owing to race.)
Update: It's closed to 50-47 Clinton, with 83 percent in. Looks like a big batch of votes just came in from Jackson County. Most of the votes left are from St. Louis. Gonna be really close either way.