Senator McConnell is being bashed by fellow Republicans for new comments from his upcoming memoir in which he refers to President Trump as “stupid,” “despicable,” and a “narcissist,” along with other harsh comments about fellow senators. He described the MAGA movement and its adherents as fundamentally “wrong” about critical issues. 

Excerpts from an advance copy of “The Price of Power” are being disclosed to members of the press, including comments about Trump’s responsibility for the January 6 riots, the seriousness of the MAGA movement, and the policies put forth by some of the hard-right members of Mr. McConnell’s own Senate conference. 

“I think Trump was the biggest factor in changing the Republican Party from what Ronald Reagan viewed and he wouldn’t recognize today,” Mr. McConnell told Michael Tackett of the Associated Press, who is writing the senator’s biography, which was first shared with CNN. 

Mr. McConnell tells Mr. Tackett that Trump has “done a lot of damage to our party’s image and our ability to compete” over the past decade.

“Trump is appealing to people who haven’t been as successful as other people and providing an excuse for that, that these more successful people have somehow … cheated and you don’t deserve to think of yourself as less successful because things haven’t been fair,” Mr. McConnell said.

Despite Mr. McConnell’s takedown of his party’s presidential nominee, he will still support Trump and other Trump-aligned Republicans in this year’s elections. He formally endorsed Trump in March after the former president became the presumptive GOP nominee, and the two met on Capitol Hill over the summer, along with other Senate Republicans. 

Other excerpts of the book that have been reported include an audio diary that Mr. McConnell has apparently kept for years. In those recordings, the senator says Trump bears responsibility for the Capitol attack on January 6, 2021, which he has said for years, though Mr. McConnell also reportedly said that Trump should face criminal charges for his actions. 

Mr. McConnell announced earlier this year that following the 2024 elections, he would not seek another term as Republican leader in the Senate. Having led the conference since 2007, Mr. McConnell has already secured his position as the longest-serving Senate party leader in American history. 

Mr. McConnell’s decision to stir the pot in such a way just ahead of the November election has rankled some of his Republican colleagues in the Senate. The conference is set to choose a new leader before the end of the year. Only three lawmakers have stepped up to run to replace Mr. McConnell, including the current Senate minority whip, Senator Thune; Mr. McConnell’s former top deputy, Senator Cornyn; and Senator Scott of Florida, who previously ran against Mr. McConnell after the 2022 elections as a hardline conservative, arguing no compromise should be made with Democrats. 

In the biography, Mr. McConnell said Mr. Scott was trying to make himself into “a victim” after the Florida senator, as chairman of the National Republican Senatorial Committee, failed to win back the Senate in 2022. Mr. McConnell highlighted Mr. Scott’s infamous plan to have all federal legislation “sunset” every five years — including entitlement programs like Social Security and Medicare — which was used by Democrats in their campaigns two years ago. 

Senator Lee, who proudly describes himself as a member of the MAGA wing of the party, said on Thursday that Mr. McConnell’s comments about Trump and other Senate Republicans are “indefensible.”

“We must have clarity from the candidates running to replace McConnell on where they stand on these attacks. They must be clear on how they plan to lead the conference, and on the role of its members,” Mr. Lee wrote on X. “Remember: McConnell’s [super PAC] has withheld campaign support from Ted Cruz and Rick Scott this election season, an incomprehensible move for a Senate GOP ‘strong leader’ who wants to keep Texas and Florida and gain a majority in the Senate.”

“I’ve given Mitch McConnell every benefit of the doubt over the years. But this is insane. With Republicans like this, who needs Democrats?” a popular conservative commentator, Michael Knowles, wrote on X. 

Mr. Scott, who has found himself in a surprisingly close re-election race in Florida, according to polls, did not immediately respond to a request for comment.