In a further sign that that party is uniting around Barack Obama in order to prevent Hillary Clinton from taking the fight past tonight, Hillary has just lost a high-profile liberal member of Congress who supported her: Maxine Waters of California, who has just re-endorsed for Barack Obama.

"As an outspoken advocate on issues critical to women and children, I have great admiration for Senator Clinton and know first-hand her commitment to our country," Waters said in a statement released by the Obama campaign.

"However, our nation is at crossroads. Now is the time for us to unite so that real change is possible in November."

According to the Obama camp's math, he is only 12 delegates away from securing the nomination, including Waters and three super-dels from Delaware in their latest e-mail release.

Obama's haul of super-delegates is turning out out to be very heavy today -- and that's before any actual votes are counted from tonight's primaries, increasing the likelihood that he will clinch the nomination imminently soon.

• Former President Jimmy Carter, who had dropped hints for quite a while that he was for Obama, and officially confirmed the news with the Associated Press.

• South Carolina Congressman John Spratt.

• DNC member Ralph Dawson, from Hillary Clinton's home state of New York.

• Massachusetts DNC member Deb Kozikowski.

• Massachusetts Congressman John Olver.

• DNC member Joyce Beatty of Ohio.

• DNC member Jennifer Dechant of Maine.

• DNC member Maria Chappelle-Nadal of Missouri.

• State party vice chair Carnelia Fondren of Mississippi.

• DNC member John Perez of California.

• Six Michigan super-dels, who each count as half a vote: Detroit Mayor and DNC member Kwame Kilpatrick, Congresswoman Carolyn Cheeks Kilpatrick, and DNC members Debbie Dingell, Rick Wiener and Joyce Lalonde, and state party vice chair Tina Abbott.

• Florida DNC member Diane Glasser, who counts as half a vote.

• DNC member Kamil Hasan of California, who has switched from Clinton.

• DNC member Ben Johnson of the District of Columbia, who has switched from Clinton.

• Congresswoman Maxine Waters of California, who is defecting from Hillary Clinton.

• Delaware DNC members Harriet Windsor and Rhett Ruggerio, and state party chair John Daniello. Ruggerio has switched from Clinton.

• Congressman Dennis Moore of Kansas.

• Maryland DNC member Bel Leong-Hong.

• Oklahoma party chair Ivan Holmes.

• Congressman Bob Brady of Pennsylvania.

Score: Obama +23.5, Clinton -3.5.

The Obama camp also rolled out a list of endorsements by Edwards pledged delegates, totaling ten for the day.

According to the Obama camp's most recent math, he is only eight delegates away from securing the nomination.

(ed. note: This post will be continually updated to reflect new endorsements.)

Barack Obama's campaign has been racking up more super-delegate endorsements today, as the campaign counts down to clinching the nomination. The names so far:

• DNC member Joyce Lalonde of Michigan, who counts as half a vote.

• Rep. Carolyn Cheeks Kilpatrick of Michigan, who counts as half a vote.

• Rep. John Olver of Massachusetts.

• DNC member Maria Chappelle-Nadal of Missouri.

The score so far for today: Obama +3, Clinton +0. Obama now has 2,080.5 delegate votes to Clinton's 1,916.5, and the Obama camp's math says he is 36.5 delegates away from securing the nomination.

Also, the winner of the Montana primary tonight will be able to count on a five-vote bonus -- the governor, both Senators, and the state party chair and vice chair will reportedly pledge their votes to the winner of the state's primary at the moment the media calls the race. Obama is favored to win that one.

As I noted below, a bunch of uncommitted Senators met yesterday to discuss how or whether to go public with an endorsement, but Obama advisers don't expect a group of them to endorse today.

Now there's more confirmation of this. The Rocky Mountain News talked to Senator Ken Salazar about what went down at the meeting; the Senators reached no endorsement agreement, and furthermore...

"I could make the argument for either one of them," Salazar said about Sens. Barack Obama and Hillary Rodham Clinton. "Many people can make the argument that maybe the best thing would be for both of them to be on the same ticket."

Salazar said the possibility of a joint ticket was discussed at today's meeting. "There was some of that discussion, but there's no conclusion," he said.

Marc Ambinder says Salazar is trying to broker a joint endorsement for Obama. It seems clear to me that the dynamic just hasn't changed for many prominent super-delegates, even at this late date -- there's no real incentive to endorse either one, given that it risks alienating some of their constituents, and they want to give Hillary a chance to leave the race gracefully.

If Hillary stays in after Obama gets the magic number, of course, that will no longer apply, to put it mildly. The thing to watch for is whether there will be public super-del pressure on Obama to offer Hillary the Veep slot.

In a further sign that uncommitted super-delegates are poised to step in and endorse Barack Obama in order to end the Democratic race after tonight, uncommitted Congressman Jason Altmire (D-PA) told the New York Times that while many super-dels are sitting still for the moment, there is definitely an urge to get the race over and done with by the end of the week.

"We want to hear from Senator Clinton; she deserves the right to make her statement," said Altmire. "But I'm not fine with it proceeding. I think it's incredibly damaging at the end of the process for it to continue on."

Hillary rolls out her first super-del of the day, Louisiana Democratic State Party Chair Chris Whittington.

Tellingly, the Clinton camp's release on this took care to highlight a quote in which Wittington explicitly citing a belief in Hillary's superior elecability to explain the endorsement -- and stressed that other super-dels have a responsibility to follow suit.

"There is no question that she is the strongest Democrat to go toe-to-toe with John McCain in a general election," Wittington said. "It is our responsibility as automatic delegates to choose the candidate we believe best fit to beat Senator McCain."

Still, the math appears inexorable: The Obama camp's numbers put him 44 delegates away from the magic number of 2,118.

In a blow to any hopes Hillary Clinton might have of continuing the fight for super-delegates after Tuesday, a top supporter is now saying she should admit defeat after the voting is all over.

"It does appear to be pretty clear that Senator Obama is going to be the nominee," said former Iowa Gov. Tom Vilsack. "After Tuesday's contests, she needs to acknowledge that he's going to be the nominee and quickly get behind him."

If Hillary tries to keep the contest going after the primaries, it seems likely that some of her backers could withdraw their support.

It's not even 9 A.M. in the morning after Hillary's big Puerto Rico win, and the Obama campaign has just rolled out its second super-del of the day: Democratic State Party Chairwoman Nancy DiNardo.

The key, again, is whether Obama will rack up enough super-dels in the next two days to be able to reach the magic number of 2,118 by Tuesday night. He's now 44 away.

Hillary Clinton has floated a new way to defy the Democratic math, which all points to Barack Obama clinching a majority of total delegates later this week: Court Obama's super-delegates to switch over. "One thing about super-delegates is that they can change their minds," Clinton told reporters on her campaign plane last night.

This is all above board in theory, as super-delegates can change their minds at any moment without betraying any sense of small-d democracy. In practice, it's hard to see how Hillary could keep such a fight going all Summer long -- it's more likely that her own super-delegates would start switching to Obama in order to send a clear message that the race is over.

Obama could, in the next couple of days, win over enough super-delegates to be able to clinch the new magic number of 2,118 delegates on Tuesday night.

And despite Hillary's win in Puerto Rico yesterday, Obama gets an early start this morning, rolling out the support of DNC member Jerome Wiley Segovia of Virginia.

According to his campaign's count that puts him 45 away from clinching the nomination.

Buried in today's big New York Times piece on the state of the Democratic Primary is a curious quote from leading Obama supporter Bill Richardson, in which he appears to suggest that there are benefits awaiting super-delegates who've endorsed him before the voting ends -- and not those who wait:

Gov. Bill Richardson of New Mexico, who endorsed Mr. Obama nearly two months ago, recently called Gov. Bill Ritter Jr. of Colorado, who has yet to endorse a candidate. "Hey, Ritter!" Mr. Richardson said. "After June 3, it means nothing. Those who take a little bit of a risk, he'll remember you."

This is a bit hard to read. The sourcing is unclear, and Richardson's tone seems somewhat jocular. But the message is pretty clear.

Richardson doesn't appear to be speaking for the Obama campaign at all here. If this is a message that's being delivered to other super-delegates, it seems like the sort of talk Obama wouldn't -- and shouldn't -- condone, and I suspect he'd denounce it if asked.

MSNBC reports on a possible new compromise for Florida and Michigan:

This plan would halve the votes for all of the Florida delegates, netting Clinton 19 and, more importantly, counting that popular vote. But Michigan's primary results would not be accepted and, instead, that state's delegates would simply be split 50-50 between Clinton and Obama.

All of the delegations, under this compromise, would be seated in full, but each delegate's vote would be counted as 0.5, including the superdelegates.

MSNBC says this is gaining some traction in the right circles, adding that it would make the new magic number for victory become 2,118.

So, under this scheme, Hillary would net an overall total of 19 delegates from Florida. Add in Michigan's 50-50 split, and she would get roughly 84 delegates, Obama would get 65. That would hardly make up much ground for her, since at that point it would bring the total delegate counts (assuming no others decide in the next couple of days) to this:

Obama 2,046

Hillary 1,866

That would mean she'd still have to pull in a huge percentage of the remaining super-dels to prevent Obama from getting to the magic number of 2,118. Of course, she could argue that Florida's popular vote should now be added to the tally, though even that would almost certainly fail to overcome his lead by that metric.

Here's one other nugget I meant to bring you from yesterday's Obama campaign conference call: Obama top adviser David Plouffe said flatly that reports saying Obama has a massive number of super-delegates secretly banked to roll out after June 3rd are untrue.

"That's not accurate," Plouffe said, when asked about such reports. "You know, we announce super-delegate support as people commit to us. We have done three so far today. So we are announcing them as they pledge their support to us...no, we do not have a bunch of super-delegates in our back pocket."

There's a simple reason that these rumors of blocs of super-dels secretly plotting to move en masse keep proving to be false: This isn't how the dynamic actually works. The reality is that getting indivdiual super-dels to commit -- and getting them to go public -- is hard enough on its own, let alone getting them to do so in a big group.

Once either campaign has got an individual super-del privately locked down, it rushes that super-del out the door and makes it public as quick as possible, in order to make it official. The campaigns don't privately hoard super-dels, because to do so would risk losing them.

Bill Clinton has taken another step in the Hillary campaign's arguments about the Democratic popular vote, bluntly telling a crowd in Puerto Rico that super-delegates and the party as a whole will have to judge just how much caucuses should matter.

"And the party will have to decide whether they believe the caucuses -- where you get about one delegate for 2000 votes -- are more important than the primaries where you get one for 12,000," Bill told the crowd.

This is on top of a line from Hillary's new letter to super-delegates, in which she predicted that by the time this race is over, she will have won more pledged delegates from primaries -- a subtle message that Obama's victories in caucus states are illusory as far as how much support they truly represent for him.

On the Hillary conference call, there was a bit of a curious moment: Harold Ickes, who's Hillary's chief delegate hunter, seemed to suggest -- perhaps wishfully -- that she would wind up the primaries only "a few" delegates behind Obama.

By midnight on June 3rd, Ickes said, "neither candidate will have achieved the number to clinch the nomination, and each candidate will have to make their case." Referring to the super-delegates, Ickes continued: "Hillary will probably have to get a few more than Obama at that point."

But a bit later, when Ickes was pressed to say how far behind she'd be in delegates once the voting concluded, he conceded: "It will be over 100." It seemed clear from the context that he'd factored in a Florida and Michigan solution to get this number.

So where are we, then? By one count, there are roughly 197 remaining uncommitted super-dels.

Assume for the sake of argument that none of these decide between now and June 3rd. And assume she ends up with 100 delegates less than Obama, as Ickes predicts.

She would then need at least three-fourths of those nearly 200 super-dels to support her -- and not Obama -- in order to overtake him. That's hardly "a few," obviously.

Signaling a renewed push to super-dels in advance of Saturday's meeting on Florida and Michigan, Hillary has sent a letter and memo today directly to the super-dels that once again presses her electability case and appeals to them for support.

In the letter, Hillary continues to try to argue that the Dem primary electorate has not rendered a clear verdict on their choice of nominee, the cornerstone of her strategy to get super-dels to focus on electability:

In addition, when the primaries are finished, I expect to lead in the popular vote and in delegates earned through primaries. Ultimately, the point of our primary process is to pick our strongest nominee - the one who would be the best President and Commander in Chief, who has the greatest support from members of our party, and who is most likely to win in November. So I hope you will consider not just the strength of the coalition backing me, but also that more people will have cast their votes for me.

Her memo includes maps and polling to make her electability case -- including, as Ben Smith notes, Karl Rove's electoral maps.

Available in our Document Collection are the letter, the memo, and a collection state-by-state general election polling.

I want to heartily recommend Hendrik Hertzberg's discussion of Hillary's popular vote endgame in the current New Yorker. Hertzberg brings to his analysis a level of nuance and fairness that's been missing from much writing on the subject.

After noting that the popular vote has "no official significance" in our nominating process, Hertzberg breaks down all the different ways of counting the popular vote -- with or without caucus states; including and not including the vote counts in Florida and Michigan, in all their permutations -- and concludes that Obama leads by most counts. He will be the nominee, Hertzberg says...

In a nominating process, especially this one, the "popular vote" is an elusive phenomenon. RealClearPolitics.com, an independent Web site whose numbers political reporters and operatives tend to trust, maintains six separate tallies. At the moment, Obama leads in four of them...

Next week, after the three remaining primaries -- Clinton is expected to sweep the largest of them, Puerto Rico's -- the likelihood is that each candidate will be able to point to "metrics" showing that he or she is the people's choice. Obama will almost certainly have the better case, especially in view of opinion polls showing that his national lead among Democrats has been growing, but the reality is that the two have been almost equally strong. Obama will remain the leader in the delegate count, owing largely to a more astute strategy, and he will be the nominee. If there is a loftier lesson, it is that the nominating "system"--and not just in the Democratic Party--is an irrational mess.

Hertzberg's analysis is noteworthy because he appears to be able to allow several ideas to coexist in his head simultaneously, which quite an achievement these days.

For instance, Hertzberg rightly criticizes Hillary's over-the-top rhetoric about the sanctity of voting, and rightly pillories her "we're winning the popular vote" formulation.

But he doesn't indulge in superfluous speculation about Hillary's motives, and also makes the perfectly legitimate suggestion that our screwed up nominating system -- in addition to Hillary's gaming of it -- is also to blame for the current state of the political conversation. Even if you soundly reject Hillary's arguments as pure Lady-Macbethian cynicism, and even if you think they'll fail, which they almost certainly will, the fact remains that it is within her rights under party rules to make them to super-delegates, and super-delegates are free to listen to them if they wish.

What's more, Hertzberg also insists on making a nuanced argument, rather than a simplistic one. He allows for the fact that the popular vote does carry some weight as a metric with Democrats, and possibly even super-delegates, suggesting that its significance shouldn't be blithely dismissed. At the same time, he accurately notes that Obama is winning by most ways of counting the popular vote, and that ultimately only the delegate count officially matters -- meaning Obama will win the nomination. Yes, all these ideas can coexist.

Hertzberg's last line is a bit overheated, but it's a good piece. Read the whole thing.

Late Update: On reflection, I actually think Hertzberg's whole last graf is over the top, but I still think on balance this is one of the fairer analyses of the situation we've seen.

In a piece for The Politico, prominent Hillary supporter Lanny Davis lays out what he calls compromise proposals for Michigan, and urges the Rules and Bylaws Committee to act accordingly:

The Rules Committee has several options. The fairest would be to allocate those 57 [uncommitted] pledged delegates, to Clinton and Obama by the same ratio of their standing to one another in the average of the most recent Michigan statewide polls prior to the Jan. 15 primary. Or perhaps one Solomonic compromise, more generous to Obama than to Clinton, would be to divide the remaining delegates approximately 50-50 between the two of them, 28-27 (giving Clinton the extra delegate since she led in all the latest statewide polls prior to Jan. 15).

On Florida, Davis proposes allocating the delegates based on January's voting. The Hillary camp is officially insisting that the delegations get seated according to the voting in both states, so this piece by Davis can be taken as a hint of compromises on Michigan that the Clinton team might be willing to embrace.

The two solutions Davis proposes above for Michigan will be a tough sell. That's because they both would give her a sizable chunk of the "uncommitted" vote, which is to say that she would get a significant portion of voters that didn't vote for her, even though she was one of the choices on the ballot.

Separately, many of you have asked why it is that Obama won't simply agree to seat the delegations according to the voting, since that won't erase his lead in pledged delegates. One reason, as I understand it, is that Obama advisers don't want her to even come close in the pledged del count (not to mention the popular vote, which is another matter). This could make it that much easier for the Clinton camp to try to spin super-delegates into thinking that no popular verdict was rendered in the primary. It's far-fetched indeed to imagine that folks will buy that argument at any rate, but this is part of what drives Camp Obama's thinking.

As he inches his way closer and closer to the nomination, Barack Obama starts off the morning with the first super-delegates announced today.

Obama was endorsed by three supers from Hawaii: State party chair Brian Schatz, vice chair Kari Luna, and newly selected add-on delegate James Burns, a retired judge.

The latest total delegate numbers, according to DemConWatch: Obama 1,976, Clinton 1,779. Obama only needs 50 more delegates to clinch the nomination, not counting Michigan and Florida.

After a relative lull in super-del movement yesterday, Obama has picked up some new momentum this morning with two new endorsements -- including a defection from Hillary Clinton's column.

The two new supporters are Congressmen Jim Costa and Dennis Cardoza, both of California. Cardoza used to be a Hillary backer.

According to the Obama camp's numbers, he only needs 59 more delegates to clinch the nomination, not counting Michigan and Florida.

The score thus far today: Obama +2, Clinton -1. According to DemConWatch, Obama has 1,964 delegates to Clinton's 1,780.

Hillary advisers have publicly said that they expect a Dem nominee to be chosen by early June, but it looks like Hillary is envisioning a scenario under which this contest could go all the way to the convention, after all:

BOCA RATON, Fla. - Hillary Rodham Clinton says she is willing to take her fight to seat Florida and Michigan delegates to the convention if the two states want to go that far. In an interview with The Associated Press, Clinton was asked whether she would support the states if they continue the fight.

The presidential candidate said Wednesday, "Yes I will. I will, because I feel very strongly about this."

Could this really happen? Could Hillary take the battle over Florida and Michigan all the way to the convention? It's possible, but unlikely.

The next major step along the way is May 31st, when the Rules and Bylaws Committee meets to consider what to do about Florida and Michigan. For reasons that we'll explain here in more detail tomorrow, it's likely that the RBC will successfully vote on some sort of solution to get them seated in some fashion.

If that doesn't happen, the next stop is the Credentials Committee in late June. Hillary supporters are outnumbered on the Cred Committee by Obama supporters. DNC chair Howard Dean also controls a bloc of members. In theory, if the Cred Committee didn't reach a solution to Hillary's liking, her backers could introduce a minority report at the convention.

But this is unlikely to happen in reality. She says she'll take it this far if the state delegations want to, which seems unlikely. And without the states as cover, her backers on the committee seem unlikely to take this step, too, because such an effort would almost certainly fail, and her backers -- some of whom have their own careers to think about -- would take the blame for the ensuing chaos.

In short, it's highly unlikely that this will come down to the convention. But it's not impossible. More on this in some detail tomorrow.

The Obama campaign has just released its official delegate tally after last night's voting. They claim they are now 62 delegates from securing the nomination.

Here are their totals from last night:

Oregon: Obama 31, Clinton 21

Kentucky: Obama 14, Clinton 37

And here are the Obama camp's totals overall:

Edwards pledged delegates now supporting Obama: 9

Obama Pledged Delegates: 1,647.5 (20.5 more than needed for the majority)

Obama Superdelegates: 307.5

Obama Total Delegates: 1,964

That puts them within 62 total delegates of 2026, which the Obama camp is pointing to as the magic number. The Hillary campaign, of course, is disputing this, arguing that Florida and Michigan should be seated.

Right now, we can't be certain of how the Rules and Bylaws Committee will rule on Florida and Michigan on May 31 or how this will affect the nomination battle. Suffice it to say, however, that as Obama's total continues to mount, it becomes more and more likely that he will secure the nomination even if the RBC sat the two states' delegations in precisely the manner Hillary hopes.

And that's something that very likely won't happen, anyway.

In a sign that they're trying to seize some momentum after the primaries last night, the Hillary Clinton camp is first out of the gate with a super-delegate endorsement this morning, coming from Ohio add-on delegate Craig Bashein.

Barack Obama still leads in super-dels, though, which are essentially Hillary's last chance to win the nomination since he clinched the pledged-del majority.

The latest super-delegate numbers from DemConWatch: Obama 304.5, Clinton 278.5. With both pledged and supers added together, Obama leads with 1,961 against Hillary's 1,780.

Not counting Michigan and Florida, Obama only needs 64 more delegates to clinch the nomination -- and adding the two rogue states into the mix wouldn't radically change the math, either.

Late Update: Obama has picked up his own super, Congressman Joe Courtney of Connecticut.