NBC political director Chuck Todd has just explained the math going forward for the Clintons and it's very tough.
Todd basically concludes the Clintons really will need 60% plus margins in Ohio AND Texas to stay in the race. For perspective, the Clintons only got to 57% in New York, and with the exception of Arkansas have never gotten to 60% anywhere (52% in Latino heavy Cali).
Howard Fineman just reported that he's been in touch with his sources inside the Clintons campaign who have conceded that they cannot use superdelegates to strip the nomination from Obama if his lead in pledged delegates is more than a very small margin.
More importantly, it's becoming increasingly clear the superdelegates have no interest in taking the nomination from Obama if he has more pledged delegates.
Bottom line: The superdelegates will rally to the candidate with the most pledged delegates to end any possible controversy and push the nomination over the threshold to prevent a divided convention. Exactly as it should be.
UPDATE: Here's Fineman,