The end game: Primary season ends tomorrow

For those who have moved on from the Democratic primary, it's easy to forget that tomorrow is the last primary day as South Dakota and Montana go to the polls. The Obama campaign is working overtime to convince superdelegates to rally around him in the coming days for the Illinois Senator to reach the magic number of 2,118 and claim the nomination.

Before we get there, however, we have to get through two more primaries and new polls today suggest that those might not be as much of formalities as we expected. Obama is heavily favored to win both South Dakota and Montana but two new ARG polls tell a different story:

• In Montana, a state with 16 delegates, Obama is barely ahead 48% to 44%. The two are tied among registered Democrats and Obama gets his advantage from independents.

• In South Dakota, a state with 15 delegates, ARG finds Clinton trouncing Obama 60% to 34%.

Whatever tomorrow's results, it is unlikely they will have a big impact on the nomination and even on what superdelegates think. The two states combined offer 31 delegates and the popular vote should not switch dramatically because of tomorrow's result as there should not be that many voters. However, even a single victory would allow Clinton to score a very rare upset. When is the last time a candidate benefited from a surprising victory? We have to go back to February, when few people were expecting that big a margin for Obama in Maine and Wisconsin and his victories in Delaware and Connecticut on February 5th were surprising. Overall, it is telling of how significant a lead Obama built in February that Clinton's 30%+ wins in WV, KY and Puerto Rico coupled with a suggestion of a coming upset could look so irrelevant to the nomination quest.

Should Clinton have a good night tomorrow, it could also impact her thinking process about whether she ought to withdraw from the race. Her campaign has sent conflicting signs in the past few days. First, Clinton has stated that she had not lost hope of convincing superdelegates that have already declared for Obama to change their mind as they are not pledged to any candidate even after they declared; Terry McAuliffe suggested that he was "hearing things." This is an essential argument if Clinton wants to justify her staying in the race past once Obama passes 2,118. Second, the campaign has kept the door open to contesting the legitimacy of the Michigan seating and the RBC's decision which they are suggesting they might take all the way to the convention.

On the other hand, there have been insistent suggestions that Clinton is looking to suspend her campaign this week, perhaps even endorsing Obama as early as this Friday. The Obama campaign is already in discussion with Clinton staffers about integrating them to his team, and Ben Smith suggests that Clinton's announcement could occur as early as tomorrow. Indeed, he notes that Clinton is organizing her election night party in New York City in a larger-than-expected facility to which she has invited her top donors, which could signal something a bit more significant than expected. Also, Marc Ambinder reports that Clinton staffers are being told to return their receipts by the end of this week, another sign that the campaign is preparing for the end.

If the superdelegate tsunami that will start once the primary season is over is as huge as Obama is hoping for, it would make it impossible for Hillary to remain in the race. There is only so many declared superdelegates she can hope to switch and a more satisfactory seating of the Michigan delegation would only net her so many additional votes. CNN reports that most of the 17 remaining uncommitted Senators will endorse Obama this week, after the end of voting, though Harry Reid should not do so. Note that Clinton won the support of two supers today (one from Louisiana and one from New York) while Obama was endorsed by four who count as three (as there are two from Michigan, apart from one from CT and one from VA).

In retrospect, the Democratic primaries have been very predictable, with most of the results since early February determined by demographic factors more than anything else. But Clinton's intentions have always been much harder to understand and even harder to predict, making it that much more difficult to foresee what will happen in the coming days. But there is no question that most people in the Democratic universe are now looking to put a close to the primary and they will do everything they can to bring an end to the Clinton-Obama storyline starting tomorrow night. If Florida and Michigan were holding re-votes tomorrow as once seemed very possible, June 3rd would be a much more climactic day and one in which Clinton would actually have a plausible path to save herself. But now even an unexpected Clinton triumph tomorrow should not change the race's closing dynamic.