It's fairly apparent that both John Kasich and Marco Rubio will stay in the Presidential race at least through March 15. They are the only candidates with any hope of preventing Donald Trump from winning either state. Since the states are winner-take-all, either Trump gets all the delegates or one of them does. It appears likely that at some point after that both will drop out, leaving Ted Cruz one-on-one with Donald Trump.
Ted Cruz has built up a brand with the idea that establishment Republicans and moderates hate him. It sells well to an anti-establishment conservatives. The problem is that he’s not going for the anti-establishment conservatives nomination. He’s going for the Republican nomination and the Republican party includes establishment Republicans and moderates he needs those to vote for him. There are also non-establishment Republicans and libertarians Cruz has pissed off. If he has the field to himself he has to consolidate the Republican vote to beat Trump. He can’t have them thinking, “Well, I don’t like Trump, but Cruz treats me with contempt. So, maybe Trump.” If you want to lead the Republican party you have to lead the whole party. (Note: We can get into whether he should lead the whole nation if gets the nomination.)
Ted Cruz needs to lay off Marco Rubio and John Kasich until after March 15. If both drop out then, the situation won’t be that the Republican party needs to line up behind Ted Cruz. No, it’ll be that Cruz needs to sell the rest of the Republican party to vote for him. Trump has made it so it shouldn’t be hard. But it’s going to take an “I’m sorry” speech from Cruz. “I know there are many out there who agree with me on the issues but haven’t like my tactics. I hear you. I will strive to win your vote to unite all the legs of the Reagan coalition. If you pick me as your nominee I will be proud to share a ballot with great Republicans like Rob Portman, Pat Toomey, and Kelly Ayotte.” If Cruz can convince Republicans that they don’t have to love him to support him, he can consolidate Republican votes.