I agree that there is  a contingent of wrong wingers in the Dems.  My own Senators have been a part of that contingent for 35 years or longer.  I suspect Montanans voted for 'centrist' democrats because they suspected the GOP was Wall Street not Main Street.  Unforunately, at the same time it was Dem on the local level,  it was GOP on the National level for 'security' reasons.  I think 'security" meant funding for the continuation of the ICBM missiles in Montana.  That was not insignificant federal money coming into the state.