Ken Paxton, the Republican candidate for the US Senate in Texas, was recorded saying Donald Trump’s midterm convention had coincided with falling poll numbers. The remark contrasts with Paxton’s public loyalty to Trump, whose endorsement helped him defeat incumbent Senator John Cornyn in the party primary, and comes as Republicans worry about losing control of Congress.

The recording, obtained by The New York Times from an attendee opposed to Paxton’s campaign, captures him saying that “everybody’s numbers dropped” after the Dallas convention. A Paxton adviser called the report misleading and said a recent poll showed Paxton leading by three points; other recent surveys have narrowly put him behind Democrat James Talarico. Trump’s super PAC has spent $20 million supporting Paxton, while polling averages show Democrats with slim leads in six competitive Senate states; losing either chamber could enable investigations of the Trump administration.