Suppose Tom Brokaw is right and Obama does indeed have 50 more Superdelegates waiting to commit.
If that's the case, then this race is indeed almost over. Here are the numbers.
The delegate counts float around a bit, with Obama having about a 100-110 delegate lead with the current Superdelegates committed. The problem for Clinton is that we're starting to run low on Superdelegates.
I'll use CNN's count since they've been pretty conservative on Obama's delegates. They have 432 SDs already pledged. That leaves 364 left. Give Obama these 50 and - being as generous as possible to Clinton here - assume that she somehow finds another 50 of her own to balance Obama's out. That gets us down to 264 Superdelegates left.
If Obama can break even tonight and pick up another 5 or 6 with Wyoming and Mississippi, she'll be down 107 with 264 left. That means she'd have to get 186 more delegates out of the remaining 264, and this is after she somehow found the 50 to make up for Obama's 50.
So she'd need 70% of the Superdelegates to break her way, assuming Obama doesn't extend her lead. It's possible if Obama has some huge scandal - and it's probably good for her to only suspend her campaign just in case - but today could mark the end of the fear of Superdelegates overwhelming Obama's lead in pledged.
If this is true (and Texas somehow manages to come through for Obama), this could be a very good day after all.