There’s been an assumption that Barack Obama would finish out the primary season with wins today in South Dakota and Montana. In Montana, it looks like Obama is indeed ahead, but there could be a Clinton upset in South Dakota — one new poll has her ahead by a significant margin. As for the popular vote, according to Real Clear Politics, the most generous (to Obama) reading has Obama ahead by four-tenths of one percent. In other readings, Clinton is ahead by as little as one-tenth of one percent or as much as eight-tenths of one percent. Whatever happens today, look for Clinton to continue to claim, with some reason, that she won the popular vote. If, as Karl Rove said on Fox on Sunday afternoon, Clinton’s goal is to muddy up the question of who won the popular vote, she has succeeded; at the very least, Obama will not be able to claim that more Democrats voted for him to be the presidential nominee than any other candidate. Obama’s partisans can argue til the cows come home that that doesn’t matter, but at least since 2000, Democratic election rhetoric has focused on the overwhelming importance of the popular vote, and of counting every vote. For Obama, winning the delegate race but losing the popular vote is much better than the other way around, but it remains a weakness.