Conservative commentator Fred Barnes is arguing that Kirk will lose his vote in the Senate after Tuesday’s special election, no matter who wins, signaling a possible GOP line of attack against health reform if it passes with Kirk’s vote.

GOP elected officials haven’t embraced that argument, and two academic election law experts contacted by POLITICO refuted the notion that Kirk will no longer be a senator after Tuesday’s election. But it’s a sign of the fierce legal and political battles likely to ensue if Brown upsets Democrat Martha Coakley in the race to fill the late Sen. Ted Kennedy’s Senate seat…

“This has now turned into a referendum on health care in the bluest state. If Brown wins, technical 60 vote aside, there are a lot of mod[erate] Ds who are going to flip and this thing will be in trouble, not dead, but delayed and possibly scaled back,” said a Democratic health care industry insider, adding that a Republican win will make it that much harder for Democratic congressional leaders to sell a final deal to their members.

Republican strategist Phil Blando agreed. He said the argument over whether Kirk’s vote will count or not is “a legal technicality in the broader political earthquake that a Brown victory would signal. The concern isn’t that you lose Kirk’s vote, but that you lose Ben Nelson, Blanche Lincoln and Joe Lieberman and a bunch of Blue Dogs.”