First Read: “Sure, Donald Trump resurrected the birther debate over Ted Cruz’s eligibility to be president (though, in fairness, Trump is right that he didn’t bring up the question by himself — he was asked by news organizations). And, yes, Trump has jabbed at Cruz over immigration. But for the most part, and certainly compared with the rest of the field, Trump and Cruz have had a bromance in the outsider/insurgent lane of the GOP contest.”

“For his part, Cruz has gone out of his way — this entire ’16 race — not to pick fights with Trump. And these numbers from our December national NBC/WSJ poll help explain why: Cruz scores higher among Republican primary voters who say they could see themselves POTENTIALLY support Trump. Cruz gets 38% of these voters, Ben Carson gets 21%, while Marco Rubio gets just 15% and Jeb Bush 7%. (Given that the poll was last month while Carson was still afloat, it’s likely that the Cruz percentage could be even higher now.) But among GOP primary voters who would NEVER support Trump, it’s Rubio who leads at 26%. These numbers drive home two points: 1) There are two completely different lanes in this GOP contest, 2) Ted Cruz has every incentive NOT to attack Trump.”