Lamont needs to do a better job of pointing out where most of Leibermans support is coming from.
Sort of. The problem with that approach is that only around 38% of his support is coming from Republicans (in this poll, at least). If you go the route of antagonizing Lieberman's supporters, you'd probably run the very real risk of upsetting even more of them rather than convincing them to support Lamont because you chastised them.
I think Lamont's only real hope at this point is for Republicans to stop flirting with Lieberman and to shift to Schlesinger at the last moment. If Schlesinger was able to siphon off 10% or so from Lieberman's supporters, then Lamont would have a real shot.