RNC Chair on Contested Convention: ‘We’re Preparing for that Possibility’ Reince Priebus no longer thinks a contested convention is a remote possibility.

 -- RNC Chairman Reince Priebus said he no longer thinks a contested convention is an extreme hypothetical and party officials are trying to be transparent to “take the mystery away from what an open convention looks like,” he said on ABC News' “This Week” Sunday.

“I think it’s possible and we’re preparing for that possibility,” he said.

If a candidate does not have the 1,237 delegates required to win the nomination outright, it sets up a contested convention, during which some delegates are freed up in subsequent rounds of voting to choose whomever they want.

Priebus said it was a common practice for party leadership to continue voting until someone reaches a majority of delegates.

“There’s nothing magical about the number. It’s 50 percent plus one,” he said, adding that it’s “highly unlikely” that anyone but the three current candidates still running for president becomes the GOP nominee in Cleveland.

“I can't 100 percent guarantee that. But I can't imagine right now sitting here believing it would be anyone but the three remaining candidates,” Priebus said.

Priebus also addressed the Stop Trump movement, and said the possibility of running a third party candidate against Donald Trump, if he becomes the Republican nominee, would doom the chances of the Republican party winning the general election.

“But it isn't likely and it's probably too late and there is no definitive answer right now as to who the nominee is going to be of our party,” Priebus said.