Rubio looks like he has switched from chasing the Presidency to a suicide mission against Trump.
I still think a Kasich pathway may open up. It's clear that the establishment hoped Rubio could win and lined up behind him as Bush's failure became obvious.
But now they are trying to save the Conservative party and Rubio is a foot soldier in that war. Throw him against Trump in a desperate attempt to wound him.
There has to be someone else the GOP gets behind. Cruz is one possibility. But can they wear that guy? I don't think so.
The only candidate left is Kasich. There is some reason they haven't drifted in his direction so far. But he looks a strong candidate for the general election. With the backing of the entire establishment, maybe he can also roll Trump over.