Democratic officials had signaled some openness to collaborating with Fox News on a debate in 2019 or 2020, saying they were trying to reach a broad national audience.

But the party came under pressure this week after the report in The New Yorker, by the veteran journalist Jane Mayer, which laid out the sometimes symbiotic relationship between Mr. Trump and the network he follows closely.

Network stars like Sean Hannity regularly advise the president, and Mr. Hannity spoke at a Trump campaign rally last year, high-fiving the president’s deputy chief of staff, Bill Shine, himself a former Fox News president. Other Fox News alumni, like Heather Nauert and Kimberly Guilfoyle, have joined the administration or Mr. Trump’s inner circle.

Ms. Mayer stated that Fox News had buried a damaging story about Mr. Trump ahead of the 2016 election; the Fox executive involved said he blocked the reporting because he did not think it was journalistically sound. Ms. Mayer also cited unnamed sources who said they were told by a witness that Mr. Trump was fed questions ahead of a Fox-sponsored primary debate in 2015. The network strongly denied that charge, and Ms. Kelly, who served as a debate moderator, has said she does not believe that her questions were leaked.

Mr. Perez said on Wednesday that Ms. Mayer’s article “led me to conclude” that Fox News was not fit to sponsor an official candidate forum.

So far, the Democrats have announced two primary debates for their candidates, which will air in June on NBC News and in July on CNN. The decision to exclude Fox News was first reported by The Washington Post.



Executives at Fox News say they are open to sponsoring another televised town hall — albeit one without the imprimatur of the Democratic Party — in the coming months. The network is free to invite candidates to appear, and candidates are free to accept. Mr. Wallace, Mr. Baier and Ms. MacCallum have each interviewed Mr. Trump during his tenure.