I think it is now crystal clear that Lieberman will be defeated on August 8. The endorsement of Lamont by the New York Times this weekend was very bad news for Lieberman and all indications are that Lieberman's campaign is gradually, but steadily, imploding.
I believe that at this point the question is not whether Lieberman will be defeated, but how badly he will be defeated. If Lamont wins with a margin of more than 10-20%, it will be difficult for Lieberman to stay in the race in November as an independent. Most likely the senior leadership of the democratic party will be forced to pressure him to drop out of the race.