I'm going to post an extended denunciation of Joe Lieberman later this weekend, but I thought it'd be good to get this point out of the way first: the fact that Chuck Schumer and a few other national Democratic bigwigs are hemming and hawing about whether to support Ned Lamont if he wins the Democratic primary isn't as troubling as it first appears. Michael Tomasky cites an example from 1980 in which Republican leaders did the same thing -- taking no position on a race for two weeks after their incumbent, Jacob Javits, lost his primary, and then eventually supporting the victorious challenger against Javits' third party bid with $235,000. In comments, Mark Schmitt offers a similar example from Connecticut in 1970.
This is the kind of behavior you'd expect from national party leaders. They're afraid of angering their incumbent by looking unsupportive before the primary ends, seeing him win the primary, and having to deal with a ticked-off senior senator for the next six years. But if the challenger wins, they fear six years of a ticked-off junior colleague who owes them nothing, and rush to his side as kingmakers. Whatever Schumer says now, I'm pretty sure he'll be backing the Democratic nominee at the end of August.