I think what will happen is Trump will take the opening primaries. Several of the lower tier candidates will lose their donors and drop out. Cruz is going to take the SEC with Trump not far behind. Several more will drop out.
By the last primaries, Bush will have a couple of states as will Trump and Cruz. Going into the convention, a decision will need to be made. Trump is the only one with options, because if Bush makes it to the convention, he is the inevitable choice of RNC.
Question here is, if Trump looks like he will be abandoned at the convention, after running a successful campaign, will he go third party or throw all his support behind Cruz?
The way I see it as of now, I would bet on a Cruz/Bush ticket. There is no reason why Bush can’t wait 8 years.
We’ll have to see how it plays out. I don’t know the specifics, but I’m told there is a sore loser law that limits Trump’s options on going third party. As far as teaming up goes, I’d rather see Trump and Cruz than Cruz and Bush.