The remarks from Paul Dans, the co-founder of the policy initiative, revealed discontent on the right about what some see as a pivot to the center.
The former director of Project 2025, a right-wing plan for what Donald J. Trump could do in a second term as president, is sharply criticizing Mr. Trump’s campaign, accusing its two top advisers of a series of missteps, lack of preparation and overconfidence that he says have jeopardized Mr. Trump’s chances in November.
The critique is the first public statement from Paul Dans, a longtime supporter of Mr. Trump, since he announced his departure from Project 2025 in late July. Mr. Dans oversaw the project for more than two years until Democrats publicized its proposals and turned it into a political liability for Mr. Trump. The former president ultimately disavowed the venture.
In an interview, Mr. Dans, a lawyer who served several roles in the final two years of the Trump administration, blamed Mr. Trump’s senior advisers, Chris LaCivita and Susie Wiles, for the episode and for the close race. He urged Mr. Trump to replace the two consultants.
“Trump should be running like Secretariat at the Belmont, but instead it’s a race to the wire,” Mr. Dans said.
His complaints reflect a discontent that has been simmering for weeks among a faction of Mr. Trump’s supporters on the right. Several media figures, activists and former Trump administration officials say they are worried by what they see as strategic mistakes this summer, followed by the campaign’s overtures to the center as it seeks to win over swing voters.
As is typical in Trump’s orbit, the complaints are rarely, if ever, aimed at Mr. Trump himself, but instead at his top aides. They recently grew so loud that the hashtag #FireLaCivita briefly trended on the social media network X.