When Senator Cornyn ran for re-election in 2014 he received a bevy of endorsements, but one was missing — that of Texas’ Junior Senator Cruz.

Cornyn easily won the primary and went on to win the general election handily, maintaining his status as the number two ranking Senate Republican.

On CNN Thursday, Cornyn indicated he has zero plans to endorse his Senate companion.

Sure, it’s only 2016, but Cornyn’s numerous attempts to bring Cruz into the fold were repeatedly rebuffed. Their relationship was further strained when Cornyn killed a would-be Cruz filibuster over the debt ceiling.

Cornyn told CNN on Wednesday that he would not take sides in a primary between Cruz and U.S. Rep. Michael McCaul, R-Austin, who is considering a run. Cruz in 2014 declined to endorse Cornyn in the primary.

“I’m not going to get involved in any primary races particularly with my colleagues in the Senate,” Cornyn said. “We’ll see what happens, but we’ve got plenty to worry about between now and November 2016 before we start worrying about November 2018.”

Cornyn said he is “not recruiting anybody” to challenge Cruz but sees “no benefit to anyone to get involved in the contested Republican primary.”

“I would sit on the sidelines and watch with interest,” Cornyn said.

When Cruz ran for Senate in 2012, beating David Dewhurst in the primary runoff, many a rank and file Texas Republican cast their lots with the Tea Party darling. And then Cruz got to the Hill. There, his roguish ways rubbed those same Lone Star Republicans the wrong way, leaving them disenchanted with their untested gamble.

Cruz is still a hometown favorite, but the widespread grassroot support that catapulted him to an unlikely 2012 victory shrunk when dropped out of the presidential race earlier this year.

Months ago, Cruz was considered all but unbeatable in his reelection bid. But after dropping out of the presidential race and declining to endorse Donald Trump in a prime-time speech at the GOP convention, Cruz may be vulnerable.

Alternatively, a poor performance by Trump in the general election may allow Cruz to make the argument that the party should never have strayed from his brand of conservatism, which is targeted at small-government purists and evangelical Christians.

Cruz and Cornyn have also been at odds over tactics in the Senate, which came to a head when Cornyn shut down a 2014 Cruz filibuster of a measure to raise the debt ceiling.

Cornyn called the action against Cruz “an uncomfortable moment.”

“Obviously I would have loved for Ted and I to be exactly two peas in a pod on everything,” he told the American-Statesman editorial board at the time.

Obamacare by holding up passage of a continuing resolution to keep the government going. Cruz was blamed by some for the government shutdown that followed; Cruz blamed President Barack Obama and Senate Democrats.

Cornyn never endorsed a candidate during the Republican presidential nominating contests. Speaking to KERA-TV in April, Cornyn said of Cruz, “Clearly, he didn’t come here to remain in the Senate. He came here to run for president.”

Cruz again refused to fall in line with party betters when he appealed to Republican voters at the Republican National Convention to “vote their conscience” rather than explicitly asking for support of the GOP nominee, Donald Trump.

On the other hand, Cornyn hopes the party will unite behind Trump.

Some speculate Rep. Michael McCaul will mount a Senate primary challenge in 2018, but McCaul insists he’s focused on winning re-election to the House. McCaul has served in the House since 2005 and is currently the Chairman of the House Committee on Homeland Security. Will he run for Senate? He hasn’t said one way or another…yet.

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