Republican National Committee Chairman Reince Priebus says it’s about time for the former primary candidates to express their full and unequivocal support for Donald Trump—or else face consequences from the party. “Those people need to get on board,” Priebus told CBS’s Face the Nation. “And if they’re thinking they’re going to run again someday, I think that we’re going to evaluate the process, of the nomination process and I don’t think it’s going to be that easy for them.”

When he was asked about the possibility that those who don’t support Trump would be penalized, Priebus said that is something the GOP will “look at.” Even though all the primary contenders signed a pledge to support the Republican candidate, Texas Sen. Ted Cruz, Ohio Gov. John Kasich, and former Florida Gov. Jeb Bush have pointedly not endorsed Trump.

Speaking on NBC’s Meet the Press on Sunday, Kasich said that “of course” he would not vote for Hillary Clinton, but he was also “no closer” to voting for Trump. Kasich is hardly keeping his feelings a secret. Earlier in the week he told CNN that it was “highly unlikely” he would support Trump.

Read more Slate coverage of the 2016 campaign.