President Donald Trump all but made official on Monday that he will not make an endorsement in the U.S. Senate Republican primary in Texas."Trump says he supports 'all three' candidates running for the GOP nomination in the Texas senate race," wrote NBC News' Garrett Haake. "Asked if he'll endorse incumbent @JohnCornyn — the President says the race has a long way to go. Primary is March 3. Runoff, if needed, in late May.""I just haven’t made a decision on that race yet. It’s got a ways to go. ... [Cornyn]’s a good man. … I like all three of them, actually. … Those are the toughest races. They’ve all supported me, they’re all good and you’re supposed to pick one. So we’ll see what happens, but I support all three."The answer is a blow to Sen. John Cornyn, whose allies have tried for months to get an endorsement from Trump to bail him out.Cornyn is trying to fend off a challenge from Texas Attorney General Ken Paxton, a far-right MAGA firebrand, as well as Rep. Wesley Hunt. Polling has generally shown Paxton leading the race, with Hunt trailing both of them.The primary has heated up in recent weeks as the candidates have gone after each other. A strategist for the Cornyn campaign posted documents purporting to show Hunt committed voter fraud in 2016; these documents, however, failed to redact personal information about Cornyn's family, prompting doxing accusations from Hunt and Paxton.