Cruz has to ask for the Rubio’s endorsement, and both sides need to decide that it will make a difference, according to sources familiar with the thinking of both senators.

Rubio and Cruz, who are more friendly with each other in the Senate than they are with longer-serving colleagues, occasionally chatted and patched up their sometime-rocky relationship on the campaign trail heading into Florida’s primary Tuesday, when Rubio was blown out by Donald Trump and subsequently quit the presidential race…

“There’s a difference between criticizing someone for the way they criticize your record and criticizing someone who’s a fake conservative and a demagogue who incites violence,” a longtime Rubio backer said. “We don’t want this guy [Trump] leading our party.”