If Rubio loses Florida it's over for him, if he still does not drop out...sorest loser ever. It's easy to predict that at the point both Rubio and Kasich drop out - Rubio after an eventual Florida race and Kasich after an Ohio race, the Republican primary would get crazy, as Cruz is as unpredictable on certain things as Trump is, I can see Carson backing Trump at some point, as for Kasich, if he wins Ohio and a few northern states, and Rubio is gone at that point...there might be something going for hi, at least to disrupt Trump enough in the more liberal states, so Cruz is competative. But then again why would Kasich work that for Cruz, I still think Kasich is holding Trump back for Rubio.
Sanders just needs to be more aggressive and he can start turning it around, he also needs to win the more and MOST liberal states like the New England ones and take this all the way to California. He should not cave into the media ejaculating all over Hillary and gatekeeping her every move.