“It’s not unusual for a high-profile guest to have an event on our property during Derby Day,” said Tonya Abeln, a spokeswoman for Churchill Downs. “But Churchill Downs is not an organizer of that event. We coordinate as is operationally necessary to ensure safe, smooth operations and that it doesn’t interfere with other guests’ activity.”

The appearance on Saturday comes at a particularly testy moment in the relationship between Trump and McConnell, the Senate Republican leader, a four-year marriage of political convenience that imploded when McConnell opposed Trump’s efforts to overturn the 2020 election.

Trump, whose power is derived from his ability to project the image of party kingmaker, seemed to relish the chance to upstage McConnell on his own turf. On Friday night, at a rally in Ohio, Trump heaped his go-to barnyard insult on McConnell, calling him “the old broken-down crow.”

The two men will not cross paths, even accidentally, this weekend. McConnell, who often attends the race, will be in Utah attending a memorial for Senator Orrin Hatch, a longtime friend, his aides said.

McConnell seldom engages with critics, and often deflects attacks by slyly embracing the slight. Earlier in the week, he hosted his annual Derby-themed luncheon for Republican senators in Washington, and he gave away bottles of Old Crow bourbon, a nod to the Trump-given nickname.

Trump’s Derby guest list is not public, but the hosts are said to include Pam Bondi, the former Florida attorney general; Richard Grenell, the former acting director of national intelligence; Matthew G. Whitaker, the former acting attorney general; and Kimberly Guilfoyle, a television personality who is engaged to Donald Trump Jr.

This being an election year, several politicians are expected to be stumping at the high-profile horse race. Gov. Andy Beshear of Kentucky, a Democrat, held a news conference in the media center Saturday afternoon. Asked about the fund-raiser, he said the Derby was “open to everyone.”

The fund-raiser will be held in what was described by Abeln as a semiprivate space, most likely in the Derby’s playground for the rich called Millionaire’s Row that sits high above the track and includes a maze of exclusive spaces, none more so than the 8,000-square-foot area simply called the Mansion.

The Secret Service has been coordinating with the track’s security team. No outside food will be allowed at the event, Abeln said, adding that “anyone who is attending this event would be getting the same experience as everyone else at the racetrack.”

Trump has attended the Kentucky Derby in the past, and last year, when Medina Spirit tested positive for a banned substance, he inserted himself into the national conversation, calling the horse a “junkie” in a statement.