The Colorado primary was another example of conservative activists beating the Republican establishment while liberal activists lose to the Democratic establishment. Tea Party favorite Ken Buck won, liberal darling Andrew Romanoff lost. Michael Bennet’s primary win follows the renomination of Blanche Lincoln and Jane Harman, though Joe Sestak did beat Arlen Specter.

One thing that complicates the Bennet-Romanoff race is that President Obama joined the party establishment in backing the incumbent while Bill Clinton supported the challenger. The Atlantic plays up Obama’s role in Bennet’s victory while this Associated Press report has Bennet hedging on that point. Bennet’s take seems to be, “Thanks for the help Barack, but don’t come back!”