“In a time when almost every public debate is defined by people lining up with their respective tribes,” Mr. Steel added, “he’s managed to alienate both.”
Mr. Comey, in remarks promoting the book, says he is trying to rouse the country to see Mr. Trump through the lens of “ethical leadership,” arguing that the president “does not reflect the values” of Democrats, Republicans or independents. Asked on ABC if Mr. Trump should be impeached, Mr. Comey said he hoped it would not happen because voters were “duty bound” to “go to the voting booth and vote their values.”
Mr. Comey has cast himself as a truth-teller before, sometimes to the irritation of colleagues or superiors. He threatened to quit his job at the Justice Department in the George W. Bush administration rather than sign off on a domestic surveillance program the White House demanded, and he refused Mr. Trump’s entreaties to back off of the investigation of Michael T. Flynn, his former national security adviser. Mr. Trump fired Mr. Comey a few months later, calling him a “grandstander” and citing the F.B.I.’s investigation into his administration’s ties to Russia.
“After he was fired, he finally became the martyr he always held himself out to be,” said Matthew A. Miller, who served as a top Justice Department official under President Obama when Mr. Comey led the F.B.I. “By doing a tour like this where you kind of get down in the gutter the way he has, you sacrifice your claim on being a martyr.”
Even before the release of his book, “A Higher Loyalty,” the White House, working in concert with the Republican National Committee, began an all-out campaign to besmirch “Lyin’ Comey” — the name of a website the party created to make the case — as dishonest, self-serving and driven by partisanship. But with his one-liners and cutting asides about the president, Mr. Comey only appeared to play into the hands of allies of Mr. Trump, who are eager to paint the former F.B.I. director as just another figure working for the president’s defeat.
And Mr. Comey has drawn bipartisan criticism with his latest efforts to explain — and, to some degree, recast — his much-criticized handling of the investigation into Hillary Clinton’s use of a private email server. Mark Mellman, a longtime Democratic pollster, said Mr. Comey’s standing had been undermined by the one-two punch of liberal attacks over his role in the 2016 election and the more recent assault led by Mr. Trump and his Republican allies.
“Trump has tried to define him as a bad operator, and the problem for Comey is that you can quote a lot of Democrats saying the same,” Mr. Mellman said.
At this point, it seems unlikely that Mr. Comey’s book or his performance in interviews to promote it will sway public opinion in a country that is already intensely polarized along partisan lines. Mr. Trump’s approval ratings have been similar for months, and the roughly 40 percent of Americans who support him have proven remarkably unshakable, while the 56 percent who disapprove will probably not change their views on Mr. Comey’s account.
While Mr. Comey is sure to captivate the public for a few days with his biting descriptions of the president and dramatic of interactions with him, the combination of the supercharged news cycle and the looming — and far more consequential — investigation by Robert S. Mueller III, the special counsel probing Russia’s meddling in the 2016 election, is sure to eventually overshadow his memoir.
“It keeps the story of cover-ups and corruption on the public radar while Mueller is doing his investigation, but Comey is just a pit stop along the way of that,” said Stephanie Cutter, a veteran Democratic strategist. “Much to Comey’s chagrin, his moment has passed. There’s nothing in this book we don’t already know. He just adds one more hole to a ship that’s already sinking.”
Mr. Comey plainly considers himself to be a figure who is above the political fray, driven and guided solely by facts. His friends and advisers say he wants the book to stir a conversation about the value of honesty.
“Telling the truth should not be seen as a political act,” said Keith Urbahn, Mr. Comey’s book agent. “It should just be the truth.”
Yet there is a twist: While he professes to be uneasy with the country’s growing polarization and appears to disdain partisanship, Mr. Comey has in effect weaponized himself against a Republican president by calling for him to be voted out of office. Mr. Comey may not want to be used as anybody’s “political battering ram,” as one associate put it, but he recognizes that is precisely how his book will be deployed.
Friends say Mr. Comey expected his memoir would be criticized because of how it would inevitably be construed: either as airbrushing history and not being honest about Mr. Trump’s transgressions, or as a self-serving and score-settling account with the man who ended his career in law enforcement.
Still, Mr. Comey’s former colleagues rejected any notion that he has transformed himself into a political actor or hurt his reputation.
“Jim Comey is as upright, honest and decent a person and public servant as I have ever met,” said Jack Goldsmith, who served with him in the Bush Justice Department.
As for his willingness to engage in Trumpian insults, invoking the size of the president’s hands, his allies argue that he is simply attempting to paint vivid scenes and does the same with the other presidents he served.
Mr. Miller, however, said Mr. Comey tends to be “at his best when he’s coloring inside the lines and following the rules,” as prosecutors are trained to do.
“What you see in the book is not just a factual recitation, but also a lot of spin on the ball,” he said.