Factor in those fifty delegates on top on Clinton needing huge victories tonight to stay competitive (which I doubt she will get), then the party greybeards may soon come to explain to her that she will withdraw gracefully or messily, her choice.
But watch the delegate count. If Clinton doesn’t make substantive gains on the race that matters — the delegate race (remember, the Clinton campaign said it was all about delegates after Iowa) — then there will be a major push from Obama and the party to shut this thing down.