Republican National Committee chairman Reince Priebus briefed GOP members of Congress Tuesday on the process of choosing delegates to July's presidential nominating convention in Cleveland, again pushing back against implications that the process is "rigged" by party bosses, Republicans in the room tell NBC News.
In the meeting, held at the party's headquarters in D.C., Priebus underscored to lawmakers that the nominee must receive a majority of votes from the delegates - 1,237 - not a plurality, as GOP frontrunner Donald Trump has suggested. And he said that, despite charges from Trump and others that the process is "corrupt," the RNC will remain a neutral umpire without picking sides, attendees said.
Also Tuesday, top Trump aide Paul Manafort held meetings with Trump's House endorsers and about half a dozen other members of Congress who are considering backing the real estate mogul. In those gatherings, Manafort outlined the campaign's outreach to lawmakers and its delegate strategy going forward.
"You can see the Trump campaign has shifted into a new mode, maybe later than it should have in my opinion, but Trump's a businessman and that's how he was running his campaign. Manafort is an expert and has a lot of knowledge in this area -- Trump is getting serious about delegate process," one attendee told NBC News.
The dueling meetings come as Republicans are bracing for the possibility of a contested convention, when no major candidate has sufficient support to win the nomination outright on the first ballot.
Priebus' pitch to lawmakers echoed what he told NBC News this weekend on Meet the Press, when he insisted that the eventual nominee must garner a majority of delegates in Cleveland.
"If Donald Trump, if he was winning the majority of votes, he'd likely have the majority of delegates. But that's not actually what's happening. He's winning a plurality of votes, and he has a plurality of delegates. And under the rules and under the concept of this country, a majority rules on everything," he said.
Trump has complained about the delegate selection process in recent weeks after individuals loyal to Ted Cruz have been picked to represent some states where Trump performed well with voters. In most cases, those delegates will be bound to vote on the convention's first ballot for the presidential winner in the state or congressional district they represent but could be free to vote for Cruz in later balloting.
After the meeting with Priebus, Speaker of the House Paul Ryan praised Priebus for his presentation to lawmakers.
"Reince was received extremely favorably. I'm so pleased that such a meticulous attorney is the head of the RNC because he is making sure the rules are the rules, that we follow the rules," Ryan said.
Earlier this month, Ryan, who had been viewed as a possible consensus candidate in the event of a party civil war, flatly ruled out the possibility of accepting the nomination of his party if the convention is contested.
The RNC head's remarks come as the committee's members prepare for their annual spring meeting in Florida, where the convention and delegate rules will be at the forefront of the conversation.