Using media appearances, e-mail, and even a political TV ad that will be timed to coincide with Comey’s appearance before the Senate Intelligence Committee, some in the GOP suggested that Comey’s reported assertions — that Trump asked him to drop an investigation into ties between Russians and a former White House aide — cannot be trusted.

WASHINGTON — President Trump’s allies launched a concerted effort to tarnish James Comey’s credibility this week, as the White House and Republicans in Congress brace for the former FBI director’s highly anticipated testimony Thursday about events leading up to his sudden firing.

Republicans are pulling out all the stops to suggest that former FBI chief James Comey cannot be trusted.

“FBI Director Comey needs to answer a simple question about his conversations with President Trump: If you were so concerned, why didn’t you act on it or notify Congress?’’ Republican National Committee operative Michael Ahrens said in an e-mail blast Monday.


The e-mail included a compilation of skeptical quotes in the media about Comey’s account of events from several congressional Republicans and one Democrat, Senator Joe Manchin of West Virginia.

The proactive volley from conservatives reveals the high stakes of Comey’s testimony, and the degree to which Republicans are attempting to inoculate the president from what could be a damaging performance. The Senate hearing Thursday is expected to be broadcast live on all three television networks.

Trump fired Comey last month and appeared to say that he dismissed the FBI director because he disagreed with the direction of the bureau’s probe into possible Trump campaign collusion with Russia to influence the 2016 presidential election.

“When I decided to [fire Comey], I said to myself, you know, this Russia thing with Trump and Russia is a made-up story,” Trump told NBC News in May.

Comey’s testimony before the Intelligence Committee, his first public comments since Trump fired him, could shed new details on explosive allegations Comey made in leaked FBI memos. In the memos, as they were reported, Comey said Trump asked him to back off the investigation into former national security adviser Michael Flynn. Because Trump’s campaign is a focus of the Flynn and Russia investigations, many critics have said the president’s request — if Comey’s account is substantiated — could be construed as obstruction of justice.


“Legally, based on what I have read, or heard on television, it does sound like obstruction of justice,” said Jill Wine-Banks, the former assistant special prosecutor during the Watergate scandal of President Richard Nixon.

This sets the stage for potentially one of the most riveting days on Capitol Hill in decades, on par with President Bill Clinton’s impeachment and the confirmation hearings of Justice Clarence Thomas — but with the added wrinkle of Trump’s unpredictable governing style.

On Tuesday, major television networks — including CBS, ABC, and NBC, as well as the usual cable channels — announced that they will interrupt normal programming to carry Comey’s testimony live.

The White House announced that Trump had scheduled a speech addressing religious conservatives around the same time Comey is expected to testify. And in another twist, one report suggested Tuesday that Trump may live-tweet his responses to the hearing.

During a public appearance Tuesday, Trump was asked for his message to Comey.

“I wish him luck,” Trump responded.

White House surrogates have not responded as generously.

A pro-Trump group called the Great America Alliance, which does not have to disclose donors, announced Tuesday that it purchased a 30-second anti-Comey advertisement called “Showboat,” a term that the president once used to describe Comey. The national advertisement, which will air on CNN and Fox News in the run-up to Thursday’s hearing, says Comey “put politics over protecting America,” and that Comey is “just another DC insider only in it for himself.”


On Monday on CNN, White House adviser Kellyanne Conway said “most of Washington detested” Comey. Former Arkansas governor Mike Huckabee, a Trump loyalist, said on Fox that Comey shouldn’t be taken seriously. Bill O’Reilly, the recently fired Fox News host who was a vehement defender of Trump, chimed in through his Twitter account.

“National media very much hoping Comey will hammer Trump during his testimony. Press should search for truth, not hope for political outcomes,” O’Reilly said Tuesday.

Senator Tom Cotton of Arkansas, a Republican member of the Senate Intelligence Committee that will question Comey, has expressed doubts about the credibility of the allegations.

“The accounts of these memos he allegedly wrote would be at least triple hearsay, what Donald Trump said according to Jim Comey according to someone who saw the memo, according to the New York Times’ reporter who had it read to him, didn’t even read it,” Cotton said Tuesday on “The Hugh Hewitt Show,” a popular conservative broadcast.

In a press briefing Tuesday, White House press secretary Sean Spicer would not say if Trump, a voracious television consumer, planned to watch Comey’s testimony.

“The president has a very, very busy day, as he does all the time,” Spicer said. “His focus is going to be on pursuing his agenda, and the priorities he was elected to do.”


Meanwhile, news organizations reported other developments Tuesday.

The Washington Post reported that Daniel Coats, the nation’s top intelligence official, told associates in March that Trump asked him if he could intervene with Comey to get the FBI to back off its focus on Flynn in its Russia probe.

And the New York Times reported that the day after Trump asked Comey to end an investigation into Flynn, Comey confronted Attorney General Jeff Sessions and said he did not want to be left alone again with the president.

On Capitol Hill Tuesday afternoon, most lawmakers strained to avoid answering questions about Comey.

Vice President Mike Pence, who was at the Capitol for a meeting with GOP leadership on its stalled health reform bill, also refused to answer questions about the upcoming testimony.

Democrats, however, said they were looking forward to hearing Comey’s recollections.

Senator Dianne Feinstein, a Democratic member of the Senate Intelligence Committee, told reporters Tuesday that the committee will ask Comey for any notes he kept on conversations with Trump. She also said she would be open to subpoenaing the information, if necessary.

Senator Mark Warner, the top Democrat on the Intelligence Committee, has said Comey’s career and integrity has been unfairly scapegoated by the White House and Republicans.

“Regardless of how you feel about Comey, that’s not how he should be treated,” Warner said Monday. “The president shouldn’t ask about an ongoing investigation. He particularly shouldn’t ask about that ongoing investigation that is connected to affiliates of the president. It would be absolutely unthinkable if the president of the United States asked the FBI director to effectively back off an investigation that was directed at some of the affiliates of Mr. Trump.”


His words reveal just how quickly things change in Washington politics.

After the election, Democrats were united in criticizing Comey for his handling of Hillary Clinton’s e-mail scandal, saying Comey’s public statements about that investigation led to her unexpected loss to Trump.

“The FBI director has no credibility,” Representative Maxine Waters of California said in January, in what became an Internet-rallying cry for the left.

Fast forward five months, and the tables have turned. Democrats are now rallying to Comey’s defense, and Republicans are questioning whether the former FBI director can be trusted.

Astead W. Herndon can be reached at astead.herndon @globe.com. Follow him on Twitter @AsteadWH