In recent months, Democrats and Republicans have called on the opposing party to return financial contributions or cut ties with prominent individuals accused of sexual misconduct. When allegations against entertainment executive Harvey Weinstein surfaced last fall, RNC Chairwoman Ronna Romney McDaniel and other GOP leaders quickly called on the Democratic National Committee, its House and Senate campaign arms and individual Democratic candidates and lawmakers to refund his thousands of dollars in donations.
Last weekend, McDaniel and Wynn hosted a fundraiser for Trump at his Mar-a-Lago resort to mark the first anniversary of his inauguration. Trump skipped the event, staying in Washington as a partial government shutdown unfolded.
On Friday, the RNC did not respond to requests for comment about a report by the Wall Street Journal that included interviews with dozens of people who have worked at Wynn's casinos or been told of his alleged behavior, including allegations that he pressured some employees to perform sex acts.
With the report, a major business executive now faces the kind of allegations that have led to the downfall of celebrity chefs, movie moguls, pro football team owners and national television news anchors. At least eight members of Congress have resigned or announced plans to retire because of similar misconduct allegations.
Wynn Resorts — the company that bears his name — saw its stock price drop 10 percent Friday in the wake of the Journal's report.
In a written statement, Wynn strongly denied the allegations, saying they stemmed from an ongoing divorce battle with his ex-wife.
"The idea that I ever assaulted any woman is preposterous," Wynn said. "We find ourselves in a world where people can make allegations, regardless of the truth, and a person is left with the choice of weathering insulting publicity or engaging in multiyear lawsuits. It is deplorable for anyone to find themselves in this situation."
Asked whether Wynn planned to step down from his RNC role, company spokesman Michael Weaver said, "Neither Mr. Wynn nor the company have any comment on that."
The DNC criticized McDaniel and the RNC for standing by Wynn, noting that when Weinstein was accused, she said candidates and political organizations "shouldn't take money from somebody who treated women with the absolute highest level of disrespect."
Wynn, a onetime business rival of Trump, became head of RNC fundraising operations a year ago next week. The 75-year-old is an outsize figure in Las Vegas, best known for bringing resorts with dancing fountains and man-made volcanoes to the Strip before selling the Bellagio, Mirage and Treasure Island hotels, under pressure from investors, to MGM Grand. He later built two glass towers adorned with his signature at the north end of Las Vegas Boulevard.
Wynn has been a frequent presence in Washington since taking the RNC role and is among a cast of several business associates, longtime aides and friends who have fallen in and out of favor with Trump.
The two traded barbs in the press through the 1990s and have faced off in court. In his book "Trump: The Art of the Deal," Trump said, "Wynn is very slick and smooth, but he's also a very strange guy."
Wynn has given more than $1.5 million to the RNC, the National Republican Congressional Committee and other party committees in the past five years, including a donation of more than $450,000 to the National Republican Senatorial Committee in the 2016 cycle. Several leading Republican members of Congress, including Sens. Ted Cruz (Tex.), Marco Rubio (Fla.) and Patrick J. Toomey (Pa.), have benefited from his cash.
There were signs Friday that the accusations against Wynn could influence ongoing congressional campaigns.
Sen. Dean Heller (R-Nev.), the most vulnerable GOP senator seeking reelection this year, received $5,400 from Wynn — the maximum individual amount permitted — in March, according to campaign finance records.
Rep. Jacky Rosen (D-Nev.), who is challenging Heller, called the reports about Wynn "horrifying and disturbing." Rosen said the RNC should remove Wynn as finance chairman and called on Heller to demand Wynn's ouster.
As of Friday afternoon, Heller's campaign had not returned requests for comment.
The Indiana Democratic Party urged Rep. Luke Messer (R-Ind.), a GOP Senate candidate and fifth-ranking member of the House GOP Conference, to call for Wynn's removal.
Michael Feldman, a spokesman for the Indiana Democratic Party, said Messer "has a real opportunity to live up to his own principles."
Messer is hoping to unseat Sen. Joe Donnelly (D-Ind.) but first faces a primary against Rep. Todd Rokita (R-Ind.). Messer has never met or received campaign donation from Wynn, a Messer campaign official said.
In 2000, Wynn gave $20,000 to the Democratic Congressional Campaign Committee, according to campaign finance records. Before backing Trump, Wynn donated $2,700 to Hillary Clinton's 2016 presidential campaign.
Joshua Dawsey, Amanda Finnegan, Anu Narayanswamy, Amber Phillips and David Weigel contributed to this report.