Bennet led the charge to promise to add a public option to the Senate reconciliation sidecar bill. Now that the House has passed its reconciliation sidecar -- and there is no public option inside -- Bennet doesn't want to mess up the process by proposing a public option. (It's not that the votes aren't there in the Senate, it's that the votes aren't there in the House.) 

Bennet's position is reasonable, but if -- a big IF -- the attention of liberals and party activists remain focused on what the health care bill lacks as opposed to what it represents and contains, and if this already isn't priced in to the stock, Bennet's primary challenge could be tougher than it is. The developing narrative here suggests that Obama Democrats like Bennet are presuming that the rising tide will lift their boats, and that the principal drag to their political fortunes has been the inability to get things done. (In a fundraising letter, Bennet notes that he is disappointed by the lack of a public option.)

Colorado holds its primary on Aug. 10. 

Standard disclosure: Michael Bennet is the brother of Atlantic editor James Bennet.