Trump surge - and Cruz’ support of Trump. Then think long term viability of each.
Even then Trump has the ability to keep going. I'm liking a lot of what he's saying/doing, just don't trust him because of his past. He knows how to use media better than anyone, and knows how to push buttons, I just can't trust him to be reflexively conservative, nor do I trust him to not deliver the nation to Hillary via third party.
Cruz will have to deal with the Trump factor, and as you imply, go long for when he finally drops out or runs third party.
Right now he has to make the debates. It's doubtful he will survive if he doesn't. It's why I think he needs more money bombs, followed by messaging bombs.