The smart bet all along in the Democratic primary race (at least since Super Tuesday) has been that the superdelegates will decide the race. Even with all that has happened since, this central fact hasn't really changed. And it's not likely to change in any of the remaining seven state contests, either. But there's a milestone approaching, and it just may be what Barack Obama needs to "close the deal" (as the current pundit-speak will have it) on the whole race.

Because while all the attention for the past three months has been on each state contest as it happens -- complete with numerical projections galore about the pledged delegates from each primary -- everyone has been largely ignoring the real "numbers story" to be told: the superdelegates.

There has also been a lot of attention paid to various numbers which are utterly meaningless. The Clinton camp has been making the argument that the "national vote count" may be crucial to her argument for winning. The Obama camp has been making the same argument about "number of states won." Neither is going to ultimately mean a thing. Because it's all about the delegates. In other words, we need to focus on the only numbers that are important -- the ones that will give the nomination to one candidate or the other at the Democratic convention.

And it's not even the pledged delegates -- the ones won by primaries and caucuses -- that really matter, because both camps agree that Barack Obama is going to cross the finish line with more pledged delegates than Hillary Clinton. Consider the fact that no matter how you call the remaining races, the pledged delegate count is going to be roughly the same after everyone has voted as it is now. Obama will lead Clinton by somewhere in the neighborhood of 150 pledged delegates on June 4th, when the last primary votes have been counted. Even if Hillary Clinton manages to get the Florida and Michigan delegates seated at the convention, Obama is likely still going to have a three-digit lead in pledged delegates.

Let's be honest, and examine the probable outcome of the remaining contests. May 3rd brings Guam to the table. It's the only caucus left, but there will only be four pledged delegates decided here. Obama will win this, but at most will only pick up two delegates (unless he gets over 87.5% of the caucus-goers, which is a serious stretch even for him). May 6th is the next "do or die" primary date for Clinton, when North Carolina and Indiana vote. If Obama sweeps both states, it may actually be over at this point. But assuming the polls are correct, Obama is going to win North Carolina handily, and Indiana will be very close, no matter who wins. Obama may gain back the nine delegates he lost in Pennsylvania here. Next up is West Virginia, where Clinton is heavily favored, but (unfortunately for her) after May 6th all the states are relatively small in their delegate counts. With the Democratic proportional allotment of delegates, this means picking up a handful in each of these smaller states, no matter who wins. So, Clinton wins West Virginia, and also Kentucky, who votes a week later. Obama wins Oregon the same day, negating this effect. Puerto Rico votes June 1st, which Clinton wins, netting her maybe five-to-ten delegates total. June 3rd is the last primary day for Democrats, when Montana and South Dakota vote. Assuming Obama wins both (he's been very strong in the Mountain West and Upper Plains states), this all translates into pretty much the same situation we find ourselves in right now.

Which means that conventional wisdom has been right all along -- it's all about the superdelegates. Which brings me to my main point. Within a few weeks, Barack Obama is going to cross a psychological barrier that may wind up as the decisive turning point in this contest. Because if things continue the way they have for the past three months, Barack Obama is about to surpass Hillary Clinton in the crucial metric of superdelegate support. He's about to have more superdelegates in his corner than her. And in the frenzy of this campaign, that may be the death knell for Clinton's campaign.

Think about it -- her entire argument, for the past few months, has been (stripped of its spin): "I can win the general election and Obama can't. I trust the superdelegates to see this, and to award me the nomination." But if Obama has more superdelegates in his corner, this argument is going to be null and void. "Let the superdelegates decide" isn't going to make much sense after they will already, in effect, have decided.

Hillary Clinton's problem is that the trend is not in her favor. And the trend is important, because as time goes on, there are fewer and fewer undecided superdelegates left for her to draw upon. And they're breaking for Obama by the stupendous ratio of three-to-one. Sooner or later, the mainstream media is going to notice this (to date, they've been spectacularly deaf and dumb when it comes to this metric). And that is the point when it will all be over for Senator Clinton.

Superdelegates are hard to accurately count, it should be noted, so the exact moment when this happens will be debatable, depending on which news outlet you trust for your numbers. But at some point in the next few weeks, it's going to be patently obvious to all that Obama suddenly has taken the lead in superdelegate support.

Personally, I use CNN's numbers, because I have consistently found them to be the most accurate in this year's race so far. But whoever's numbers you use, the trend is hard to deny. A handy graph of the superdelegate count (for those of you who are going to skip over the next few paragraphs where I dissect the numbers) shows that Obama has been relentlessly closing this gap ever since Super Tuesday, back in early February. Another of these handy graphs shows Obama's lead in pledged delegates, for comparison.

February 9th, Obama trailed Clinton by 92 superdelegates. This was largely a result of Hillary's successful "she's inevitable" theme in the early days of the campaign, which locked up a lot of superdelegates in her corner -- 223 to Obama's 131.

February 12th was when Obama passed Clinton in the total delegate count (pledged and superdelegates combined) to become the frontrunner. At this point, Clinton led him by 77 superdelegates (234 to 157). She had gained 11 in the three days intervening, but Obama had gained 26 in the same time period. This trend would continue.

By March 4th, the gap had closed to 39. Clinton had 238 superdelegates at this point (a gain of only 15 for Clinton since 2/9), but Obama had 199 by this point (a whopping gain of 68). This narrowed to a gap of only 31 a week later, as Clinton dropped a delegate (for a total of 237) while Barack picked up seven (for a total of 206).

After Pennsylvania voted this week, the trend continued. Hillary picked up another 19 delegates in the intervening six weeks, to put her total at 256, but in the same period Barack picked up 27, putting him at 233. The superdelegate gap now stands at only 23.

This, it should be pointed out, leaves only a little over 300 superdelegates who have not yet made up their mind -- a shrinking pool of undecided delegates whose math is even more daunting for Hillary Clinton to overcome before the convention than the pledged delegate math. And the trend is deadly for her: since 2/9, Hillary has picked up 33 superdelegates, while Barack has picked up 102 -- a better than 3-to-1 margin for him. The gap has shrunk from 92 to 23.

This does not bode well for Hillary's chances of securing the nomination by the actions of the remaining undecided superdelegates. But the turning point is going to come when Obama actually passes her in the superdelegate count. This could happen within the next forty or fifty delegates to announce their endorsement, if the trend continues. The only real question is (absent Obama self-destructing in some way) when this is going to happen. The trend here isn't great news, because the superdelegates have been announcing at a slower and slower pace as the race goes on. Which means it could take a few weeks, or it might also not happen until after all the primaries are over.

But whenever it happens, this will be the point when the mainstream media turns on the Clinton campaign in a big way. Once the media realizes that Hillary now has fewer pledged delegates and fewer superdelegates, her road to victory is going to be extremely hard (if not downright impossible) to visualize.

And no matter where we are in the primary schedule, it is that point -- whether Clinton realizes it and concedes, or whether she takes the fight to the bitter end -- when Obama truly will "close the deal."

-- Chris Weigant