We will find out how many of Rubio's voters will pick Cruz as their second choice, and how many will pick Trump, and how many will just stay home.
And if Rubio endorses Cruz, it will be the kiss of death for the anti-Establishment voters.
Cruz voters understand realpolitik. The enemy of my enemy is my friend. No one will abandon Cruz just because he gets some help in his campaign from someone they don’t like that much.
Did Trump voters abandon him because of the Christie endorsement or because he took on Giuliani as an advisor?