More than 20 Republican Party leaders met privately on Monday night with Republican National Committee Chairman Reince Priebus to prepare for a brokered convention, according to the Washington Post.

“The prospect of [Donald] Trump nearing next year’s nominating convention in Cleveland with a significant number of delegates dominated the discussion, according to five people familiar with the meeting,” the Post reported.

“Several longtime power brokers argued that if the controversial billionaire storms through the primaries, the party’s mainstream wing could coalesce around an alternative,” according to sources who spoke anonymously to the Posts’s Robert Costa, who also reported that advisors and allies of two Trump rivals were at the dinner.

Costa reports:

“Attendees included Ward Baker, executive director of the National Republican Senatorial Committee; Rob Simms, his counterpart at the National Republican Congressional Committee; Ron Kaufman, an RNC committeeman and Mitt Romney confidant; and pollster Linda DiVall.”

The Trump opponents in attendance included “Whit Ayres, an adviser to Sen. Marco Rubio (Fla.), and Vin Weber, an ally of former Florida governor Jeb Bush,” the report said.

The Post’s sources say Priebus remained mostly quiet during the back and forth about Trump, but at the end of the meeting Priebus and Majority Leader Sen. Mitch McConnell (R-KY) acknowledged that the Republican Party should prepare for a deadlocked convention.

The RNC’s chief strategist and spokesman Sean Spicer told Costa, “The RNC is neutral in this process and the rules are set until the convention begins next July. Our goal is to ensure a successful nomination and that requires us thinking through every scenario, including a contested convention.”

Trump was previously asked by the Post about the possibility of a brokered convention.

“I’ll be disadvantaged,” Trump stated. “The deal-making, that’s my advantage. My disadvantage is that I’d be going up against guys who grew up with each other, who know each other intimately and I don’t know who they are, okay? That’s a big disadvantage. . . . These kind of guys stay close. They all know each other. They want each other to win.”

The last time the Republican Party gathered without a nominee was at the 1976 convention.