The four took issue with a rule, originally imposed by Mitt Romney forces in 2012 to keep rival Ron Paul off the convention stage, requiring a candidate to win a majority of delegates in eight states to be eligible for the party’s nomination — a threshold only Trump has exceeded so far. If preserved, the rule could block John Kasich or Ted Cruz from competing with Trump at the convention, set for July in Cleveland.

If the committee scraps the requirement entirely, it could open the door to multiple candidates, possibly even some who never entered the primaries, competing for the party’s nomination at a brokered convention. And even a lower threshold would make it easier for Trump’s rivals to challenge him.

“I’m not a big fan of the eight-state threshold. I think that’s an artificial number,” said David Wheeler, a rules committee member from South Dakota. “It was designed to prevent Ron Paul delegates — their votes from being counted. I don’t think it’s necessary to do that this year.”