I think one answer here is that Lieberman isn’t actually all that smart. He speaks, and seems to think, exclusively in terms of generalities and broad statements of principle. But there’s little evidence that he’s a sharp or clear thinker, and certainly no evidence that he knows or cares about the details of health care reform. At one point during the 2000 recount, the Gore campaign explained to Lieberman why lowering standards for military ballots would be totally unfair and illegal, and Lieberman proceeded to go on television and subvert the campaign’s position. Gore loyalists interpreted this as a sellout, but perhaps the more plausible explanation was that Lieberman — who, after all, badly wanted to be vice-President — just didn’t understand the details of the Gore position well enough to defend it. The guy was taken apart by Dick Cheney in the 2000 veep debate.
I suspect that Lieberman is the beneficiary, or possibly the victim, of a cultural stereotype that Jews are smart and good with numbers. Trust me, it’s not true. If Senator Smith from Idaho was angering Democrats by spewing uninformed platitudes, most liberals would deride him as an idiot. With Lieberman, we all suspect it’s part of a plan. I think he just has no idea what he’s talking about and doesn’t care to learn. Lieberman thinks about politics in terms of broad ideological labels. He’s the heroic centrist voice pushing legislation to the center. No, Lieberman doesn’t have any particular sense of what the Medicare buy-in option would do to the national debt. If the liberals like it, then he figures it’s big government and he should oppose it. I think it’s basically that simple.