Possibly the most obsessive tracker of Democratic delegates is a website called Demconwatch (DCW).

DCW is counting every jot and tittle of the Obama-Clinton race for delegates. Over the last two weeks, with no new primaries or caucuses, DCW has shown Obama gaining ground by picking up new commitments from superdelegates at a much greater rate than Clinton. I had certainly noticed this trend, but the numbers are impressive as voters head to the polls today in four states, including the major battlegrounds of Ohio and Texas.

After Super Tuesday, Obama pulled into the lead among pledged delegates, but Clinton still held the overall lead because she led by almost 100 in the race among superdelegates.

This DCW graphic below tells the tale starkly. While Obama surged to a commanding lead among pledged delegates, he has also cut Clinton's lead among superdelegates by more than half. By DCW's count, the lead shrunk to 47. 

Not only have most superdelegates who have committed recently endorsed Obama, but a few who had earlier announced their support for Clinton have reneged, either moving to Obama or to uncommitted.

DCW lists every new superdelegate commitment over the past several weeks and the date on which they became aware of it. On this page (you have to scroll down to just above the comments) DCW finds that since Feb. 22 Obama has outgained Clinton among superdelegates by 23 to 4.

(By the way, in case you missed it last week, Obama's surge in that period included the endorsement of Minnesota DFL Chair Brian Melendez and Associate Chair Donna Cassutt. That brings the Minnesota superdelegate count to 8-3 in favor of Obama.)

Of course, 370 more pledged delegates will be chosen based on today's primaries, and I'm not dumb enough to speculate on how that will shake up the race. If Clinton has a good night and announces that she will stay on until the April 22 Pennsylvania primary, the next thing to watch will be whether the remaining uncommitted superdelegates decide to force the issue.