Lieberman v. Lamont is a great race, to be sure. It is a rare thing when an incumbent Senator faces serious competition in his own party's primary. Quite frankly, I think that every incumbent should be made to defend his/her seat in every election, including primaries. But that is a topic for another day.
But, what is stupid is the punditocracy (and Lieberman) declaring that if Lamont wins, the Democratic party doesn't have room for diversity of opinions.
Horsehockey, Joe. What it means is that the voters in Connecticut think that Lamont will better act on their views than Lieberman will. Only the extremists are calling for Lieberman to leave the party. "Diversity of opinions" works both ways, folks.