Rather than trying to take each other out, Cruz and Rubio should join forces to knock out Trump.  Then they can go head to head against each other.

This would involve an exchange of promises.  Rubio agrees to stay out of Texas.  Cruz agrees to stay out of Florida.  That's the sum total of their agreement.

Every thinking Republican in the country would applaud.  Even Mitch McConnell would like it.  If Trump loses Texas and Florida, he's gone.

Cruz and Rubio could team up one time, at the March 3rd debate in Detroit.  All the candidates who will be on the stage support using Article V to get a Balanced Budget Amendment – except Donald Trump.

Cruz has signed a pledge to support the efforts of the BBA Task Force.  Rubio is in favor of the Convention of States approach, which would allow a broad range of amendments that limit the scope and power of the federal government.

This sort of thing doesn't appeal to Trump.  He doesn't want to cut back on the power of the federal government.  He just wants that power himself.

That's a scary thought.