Ken Paxton, the Republican nominee for Senate in Texas, told conservative donors and lobbyists that President Trump’s midterm convention in Dallas hurt his political standing, according to an audio recording obtained by The New York Times. The recording, shared by an anonymous attendee of a private Washington fund-raiser, captures Mr. Paxton saying that the convention caused numbers to drop for everyone involved. Nick Maddux, a senior Paxton adviser, dismissed the remarks as manipulated nonsense and cited a recent poll showing Mr. Paxton leading by three points.

The event was hosted by Republican lobbyists Susan Hirschmann and Chris Brinson near Capitol Hill. Mr. Paxton, a longtime Trump loyalist who defeated Senator John Cornyn with presidential support, occupied a prime seat at the Dallas convention and used it to mingle with donors and raise money. Mr. Trump praised Mr. Paxton on stage while teasing his appearance. Since the convention, the midterm outlook for Republicans has darkened, with Mr. Paxton trailing Democratic rival James Talarico in many polls as MAGA Inc. pours $20 million into the race.