NEW YORK (CBSNewYork) — Republican National Committee chairman Reince Priebus said it would be a “suicide mission” if a third-party candidate ran against presumptive GOP presidential nominee Donald Trump in the upcoming election.

The Washington Post reported several anti-Trump Republicans, including 2012 presidential nominee Mitt Romney, are hoping to draft an independent candidate to run against the billionaire. The Post reported their top two prospects are Ohio Gov. John Kasich – who recently dropped out of the GOP race – and U.S. Sen. Ben Sasse, R-Neb.

As CBS News’ Brook Silva-Braga reported, Priebus said such a scenario would be a disaster.

“This is a suicide mission, it is not right,” Priebus told CBS’ “Face the Nation.” “And I think what people should do is take the Paul Ryan approach which is to work with Donald Trump and find out whether or not there’s common ground … as opposed to blowing everything up.”

Priebus warned that a third-party candidate would allow Hillary Clinton to become the next president.

“You’re not only changing and throwing out eight years of the White House, but you’re also throwing out generations of the Supreme Court. We could have three justices change over in the next eight years,” Priebus said.

On Sunday, House Speaker Paul Ryan said he didn’t have a timeline for unifying behind Trump.

“This is a process, we still have some time to go,” Ryan said.

Priebus told “Face the Nation” that Trump and Ryan, who met on Capitol Hill last week, do agree on many things.

“They agree on far more than they disagree on. They agree on various agenda items on Paul Ryan’s agenda,” Priebus said. “They agree on the Supreme Court, they agree on the platform of the Republican Party, they agree on abortion.”

Priebus believes that the House speaker will eventually unite with Trump.

“I think we’re going to get there, I think there’s plenty of common ground,” Priebus said.

Priebus added, “I think in the end people are going to choose the person that’s going to cause an earthquake in Washington and get something done over Hillary Clinton,” he told “Face the Nation.”

Some Republicans reportedly asked billionaire businessman Mark Cuban to launch a presidential bid. Cuban said it was too late.

Trump also responded to reports accusing him of mistreating women and posing as his own spokesman, with a tweet Sunday:

The media is really on a witch-hunt against me. False reporting, and plenty of it – but we will prevail! — Donald J. Trump (@realDonaldTrump) May 15, 2016

COMPLETE CAMPAIGN 2016 COVERAGE

Meanwhile on the Democratic side, voters will head to the polls in Kentucky and Oregon on Tuesday as Clinton works up to wrap up her party’s nomination.

On Sunday, Clinton campaigned across Kentucky, and made her case to the blue collar voters who have leaned toward Bernie Sanders in earlier contests – and also been courted by Donald Trump.

“So I know we can bring manufacturing jobs back. We need to change the tax code that gives companies incentives to move jobs out of America,” Clinton said. “We need to stop that.”

Sanders also held a rally in Kentucky, arguing that polls show he is best positioned to win in November.

“We do much better against Trump than does Clinton,” Sanders said.