Republican Texas Rep. Mike McCaul is going after Ted Cruz for refusing to endorse or support his party’s nominee Donald Trump for president.

“I think what he did at the convention turned off a lot of people,” McCaul told radio host Laura Ingraham Tuesday. “He pledged to support him. He broke his word. What he said in terms of not supporting the nominee. There’s some discontent.”

Ingraham asked McCaul about the potentiality of running against Cruz in a 2018 Texas Senate primary. The idea of challenging Cruz from the Right is already being talked about widely among conservative insiders. Heroic former Navy SEAL Marcus Luttrell’s name has also come up as a possible Cruz primary opponent.

“What I’m looking at, to be honest with you, is getting Trump elected to the White House and keeping Hillary out of there. I’m working with Giuliani on this very closely on the national security team because I’m putting the country first above myself. That’s what’s important right now to me,” McCaul said.

Cruz’s failure to endorse Trump from the stage in Cleveland led to one of Trump’s best power plays, when he interrupted Cruz’s speech to walk into the convention’s general seating area and wave to his supporters. Cruz was booed off the stage and his wife Heidi was taunted with jeers of “Goldman Sachs” by Trump delegates on the floor.