Kansas Omens

Nate Silver is worried:

It's just one poll, and it's not in a state of any enormous amount of electoral significance, but the new Rasmussen poll that shows Barack Obama trailing by 23 points in Kansas -- he had been down by just 10 last month -- is a little ominous. Obama's numbers are bad across the board: he's getting a relatively low percentage of Democrats, trailing by 17 points among independent voters, and his approval ratings are negative.