Rubio will drop out when the RNC says he can drop out. They’ve been winding him up and sending him out there to attack Trump. Left to his own devices, that is not what Rubio was doing on his own.
Look for Rubio to drop out when the FL primary comes out and he loses.
So what happened? It seemed as if the nasty campaign staff Cruz had to finally fire moved over to Rubio. If Rubio's not his own man enough to run his own campaign, he's not his own man. That just adds to the supposition that he's a total pro-invasion guy.
Then there's the overall impression. I do not like the two Cubans who were at each other's throats now tag-teaming against Trump. It looks more like an attempted coup than a campaign strategy.