Does Clinton really believe she would win?

[Mr. Morden]

Besides, Obama still could have a horrible scandal break out, especially if this Michelle Obama whitey rant tape is real.

If Obama has a huge career ending scandal, Clinton will win the nomination regardless of whether she's already dropped out or not.  Obama withdraws his candidacy, and Clinton restarts her campaign, and only needs to peel off a handful of former Obama delegates in order to win.  So really, there's no reason to hold off on dropping out just for that.