He's got to be having second or third thoughts about this. After all, if he stays as an independent, even if he does caucus with the Rats, he'll still lose all of his prized committee seats.
If anyone will have second thoughts after a Lieberman reelection, it will the Democratic caucus in the Senate. If he's the fiftyfirst vote for the Democrats Lieberman will be the best friend they ever had, forever (or until the next election, whichever comes first). He will get whatever committee seats he would have expected before his primary defeat.And I doubt that the situation would be much different if he were the fiftysecond or the fortynineth or fortyeighth Democratic vote. But for now, with the election coming up, they think they have to be distant. The thing that will really stick in their craw will be the pressure he creates to resist the left wing of the party, with the start of a presidential election looming the minute the votes are counted in November.
The Democrats are never gonna stop resenting Lieberman's running as an independent after losing the primary, but they're gonna need his vote badly if he wins.