I would vote for Schlesy! However he would be horrifically demolished.
Lamont 63%
Schlesinger 35%
Wait, I missed the UTTERLY ridiculous premise of a DEMOCRAT ENDORSING SCHLESINGER (besides myself, but that is far very different reasons). Lamont is no leftist. He disagrees with Liberman on the biggest issue in a decade, Iraq. He was thrown our for being old, dull, and not doing enough to be a Democrat. It has NOTHING to do with political ideology, however much Fox News likes to spin it like that. Lieberman would most certainly endorse Lamont, or possibly not endorse. Endorsing Schlesinger WOULD NOT happen. But if he did.... it would be closer than what I had.
Even if Lieberman would endorse Schelsinger the race wouldn't be anything closer than you originally suggested. Schlesinger may get a sympathy vote from the endorsement, but he would be absolutley demolished. He is a horrific candidate with major flaws.