As Robert Alt notes below, on Fox News this morning Bill Kristol and Brit Hume predicted a Mondale victory in Minnesota. Kristol and Hume are, I think, ignoring a key piece of Minnesota state law -- all those absentee ballots already mailed and cast for Wellstone will still be counted as Wellstone votes, even if the Democrats decide to "nominate" Mondale to fill the vacancy. (See Minnesota statute and Sec. of State explanation). So, unless the Democrats have been uncharacteristically lax in their absentee efforts in Minnesota this year (hard to imagine, given the closeness of the race and Democrat efforts nationwide in nursing homes, etc., to boost absentee votes to 30% of the total, as reported in Friday’s WSJ), Mondale would have to win a pretty big landslide on election day in order to prevail. Assuming total turnout of 2.3 million and about 5% going to minor party candidates (based on recent turnout trends, and taking into account that this is not a Presidential election year), an absentee vote of 30%, with 70% already cast (or that will be cast using the original ballots), and further assuming Democrat absentee efforts produced a 55-40% margin (first for Wellstone, then for Mondale), Mondale would have to win by more than 10 percentage points on election day in order to prevail.
I believe this is the reason that Mondale has not already committed to being on the ballot -- I expect to see litigation filed Monday asking a court to treat the absentee votes already cast for Wellstone as Mondale votes. Without that, it might be better for the Democrat party simply to urge Democrat voters to cast a vote for Wellstone and have a repeat of 2000 Missouri, if they can.