The numbers: Obama continues steady march towards nomination

Here's the superdelegate news of the day (as far as I know):

• Obama endorsed by former DNC Chair Joe Andrew, who switches from Clinton to Obama
• Clinton announces all four NY add-ons will support her campaign
• Obama announces all three IL add-ons will support his campaign
• Maryland will announce its two add-ons later today
• Update: Obama also gets TX superdelegate Joe Patrick. (Numbers updated throughout.)
• Update: Clinton picks up a CT superdelegate, bringing her total to 5 for the day (but she lost one in a switch).

Net/net: Obama picks up 5 supers. Clinton picks up 5 but loses 1 for a net of +4.

The important thing as Ben Smith and Avi Zenilman note is that these add-ons do not reflect momentum in anyway whotseover. There was no suspense about whether the IL party would support Obama, or the NY party would support Clinton. Avi also notes that 3 of CA's 5 add-ons will support Clinton and 2 will support Obama.

The key thing for Obama is that he is so much closer to the 2,024 threshold than Clinton that unless she's picking up more than two supers for each one that Obama picks up, he's doing fine. If from here on out, Obama only won 40% of of the support of supers -- he would still win the nomination.

The trendlines look much better than that.

BTW, going into today, Clinton had 261 supers and Obama had 242. Taking today's announcements into account, Clinton is at 265 and Obama is at 247.

Now, remember that Obama had 1,493 pledged delegates. He's all but certain to win at least another 200 (there are 408 left to be selected). That puts him at 1,693 pledged delegates -- minimum. Add in his 246 superdelegates plus another 2 from CA and he is at 1,942 total delegates -- 83 short of the 2,024 needed to secure the nomination. (Remember, this relies on a conservative projection of pledged delegates.)

The bottom-line is that to win the nomination, Obama needs just 82 of the 278 uncommitted superdelegates -- a bit under 30%.

None of these numbers are exact, and different sources will have slightly different estimates, but the core math is very clear: to be able to win the nomination, Clinton needs 70% of the remaining superdelegates, and there has been absolutely no indication that she will be able to achieve that number.

Also note that my numbers here are very conservative. We could also project out the unnamed add-ons, which will likely split between Clinton and Obama. At that point, Obama would need just 25% or so of undeclared superdelegates. If you throw in the members of the Pelosi club and other supers like Jim Clyburn who are undeclared but are clearly for Obama, the number is closer to 20%, if not less.

The math is our friend, my friends.