Mark the date: May 20. That night, Sen. Barack Obama's presidential campaign is planning to declare victory. At his campaign headquarters here, the number crunchers figure—with pretty solid justification—that, on that date, after the returns come in from the Oregon Democratic primary, their man will have won an outright majority of the pledged delegates to the 2008 convention in Denver.

"The die is cast," campaign manager David Plouffe told me after the early returns came in Tuesday night, revealing that Obama had won a big victory in North Carolina. According to Plouffe's math, Sen. Hillary Clinton still could win big in West Virginia and Kentucky. But even with those victories, Obama pickups in those states, plus a likely big win in Oregon, would be enough to reach the magic number: 1,627, a clear majority of the pledged delegates.

At that point, his strategists say, Obama will be able to turn to uncommitted superdelegates and say: "I've done my part." Party leaders such as House Speaker Nancy Pelosi have said, in effect, that they will support whichever candidate wins the most delegates in primaries and caucuses. And, by then, Obama will have done so. I am told that Pelosi herself may remain neutral until the convention, but that 60 or so House members who have been hanging back would be free to commit.

As things now stand, Obama remains short of the 2,025 total delegates he needs. But his campaign is determined to reach that goal by no later than the morning after the May 20 vote.

Obama strategist David Axelrod, confirming the target date, cranked up the May 20 spin machine: no Democratic nominee who had won a majority of pledged delegates has ever been denied the party's nomination, he said, and Obama was not going to be the first.

Clinton's argument, of course, is that winning a majority of "pledged" delegates isn't the real test: to her, it is the total number of delegates won, pledged and "super." More than that, Hillary argues that the 2,025 delegates needed to clinch should more properly be 2,209, if you count, as she does, the Florida and Michigan primaries. (Both states moved the date of their votes up on the calendar in defiance of the national party, and were stripped of their delegates as a result).

Clinton plans to take her case to the party's rules committee on May 31 in Washington. Obama's plan is to make it all seem moot by then, or at least by Oregon.

© 2008