The Obama campaign has sent out a tough memo this morning telling superdelegates that Obama has played by the Democratic rules (unlike Clinton, who can only win by changing the rules and moving the goalposts) and the math is the math. With out saying so overtly, the memo clearly says: It’s over. Obama will win the nomination. This pretense of an unsettled fight is ridiculous. Get on board.

They’re talking to you, Jim McDermott and Rick Larsen, our undecided Congressmen from Washington State.

Here’s the memo. Obama will be in D.C. tonight and tomorrow to make the case to the superdelegates himself.

TO: Superdelegates

FROM: David Plouffe, Campaign Manager

RE: An Update on the Race for Delegates

DA: May 7, 2008

There are only six contests remaining in the Democratic primary calendar and only 217 pledged delegates left to be awarded. Only 7 percent of the pledged delegates remain on the table. There are 260 remaining undeclared superdelegates, for a total of 477 delegates left to be awarded.

With North Carolina and Indiana complete, Barack Obama only needs 172 total delegates to capture the Democratic nomination. This is only 36 percent of the total remaining delegates.

Conversely, Senator Clinton needs 326 delegates to reach the Democratic nomination, which represents a startling 68 percent of the remaining delegates.

With the Clinton path to the nomination getting even narrower, we expect new and wildly creative scenarios to emerge in the coming days. While those scenarios may be entertaining, they are not legitimate and will not be considered legitimate by this campaign or its millions of supporters, volunteers, and donors.

We believe it is exceedingly unlikely Senator Clinton will overtake our lead in the popular vote and in fact lost ground on that measure last night. However, the popular vote is a deeply flawed and illegitimate metric for deciding the nominee – since each campaign based their strategy on the acquisition of delegates. More importantly, the rules of the nomination are predicated on delegates, not popular vote.

Just as the Presidential election in November will be decided by the electoral college, not popular vote, the Democratic nomination is decided by delegates.

If we believed the popular vote was somehow the key measurement, we would have campaigned much more intensively in our home state of Illinois and in all the other populous states, in the pursuit of larger raw vote totals. But it is not the key measurement.

We played by the rules, set by you, the D.N.C. members, and campaigned as hard as we could, in as many places as we could, to acquire delegates. Essentially, the popular vote is not much better as a metric than basing the nominee on which candidate raised more money, has more volunteers, contacted more voters, or is taller.

The Clinton campaign was very clear about their own strategy until the numbers become too ominous for them. They were like a broken record , repeating ad nauseum that this nomination race is about delegates. Now, the word delegate has disappeared from their vocabulary, in an attempt to change the rules and create an alternative reality.

We want to be clear – we believe that the winner of a majority of pledged delegates will and should be the nominee of our party. And we estimate that after the Oregon and Kentucky primaries on May 20, we will have won a majority of the overall pledged delegates According to a recent news report, by even their most optimistic estimates the Clinton Campaign expects to trail by more than 100 pledged delegates and will then ask the superdelegates to overturn the will of the voters.

But of course superdelegates are free to and have been utilizing their own criteria for deciding who our nominee should be. Many are deciding on the basis of electability, a favorite Clinton refrain. And if you look at the numbers, during a period where the Clinton campaign has been making an increasingly strident pitch on electability, it is clear their argument is failing miserably with superdelegates.

Since February 5, the Obama campaign has netted 107 superdelegates, and the Clinton campaign only 21. Since the Pennsylvania primary, much of it during the challenging Rev. Wright period, we have netted 24 and the Clinton campaign 17.

At some point – we would argue that time is now – this ceases to be a theoretical exercise about how superdelegates view electability. The reality of the preferences in the last several weeks offer a clear guide of how strongly superdelegates feel Senator Obama will perform in November, both in building a winning campaign for the presidency as well as providing the best electoral climate across the country for all Democratic candidates.

It is important to note that Senator Obama leads Senator Clinton in superdelegate endorsements among Governors, United States Senators and members of the House of Representatives. These elected officials all have a keen sense for who our strongest nominee will be in November.

It is only among D.N.C. members where Senator Clinton holds a lead, which has been rapidly dwindling.

As we head into the final days of the campaign, we just wanted to be clear with you as a party leader, who will be instrumental in making the final decision of who our nominee will be, how we view the race at this point.

Senator Obama, our campaign and our supporters believe pledged delegates is the most legitimate metric for determining how this race has unfolded. It is simply the ratification of the D.N.C. rules – your rules – which we built this campaign and our strategy around.