WASHINGTON — White House officials asked at least twice in the past month for the key witness against President Trump in the Mueller report, Donald F. McGahn II, to say publicly that he never believed the president obstructed justice, according to two people briefed on the requests.
Mr. McGahn, who was the president’s first White House counsel, declined, one of the people said. His reluctance angered Mr. Trump, who believed that Mr. McGahn showed disloyalty by telling investigators for the special counsel, Robert S. Mueller III, about Mr. Trump’s attempts to maintain control over the Russia investigation.
The White House made one of the requests to Mr. McGahn’s lawyer, William A. Burck, before the Mueller report was released publicly but after the Justice Department gave a copy to Mr. Trump’s lawyers to read. Reading the report, the president’s lawyers saw that Mr. Mueller had left out that Mr. McGahn had told investigators that he believed Mr. Trump never obstructed justice. Mr. Burck had told them months earlier that his client had shared that belief with investigators.
Mr. McGahn initially entertained the White House request. But after the report was released, detailing the range of actions Mr. Trump took to try to impede the inquiry, Mr. McGahn declined to put out a statement. The report also included comments Mr. Trump to aides about how he believed Mr. McGahn leaked to the media to make himself look good.
The episode shows the lengths the White House has gone to around the release of the Mueller report to push back on the notion that Mr. Trump obstructed justice. House Democrats have used the report to launch investigations into whether Mr. Trump abused his position to insulate himself from the investigations.
The revelations came as the Democrats increased their pressure on the White House on other fronts on Friday. The chairman of the House Ways and Means Committee, Richard E. Neal, subpoenaed the Treasury Department and Internal Revenue Service for six years of Mr. Trump’s personal and business tax returns. Democrats are also pursuing testimony from Mr. Mueller but have not agreed on a date, Representative Jerrold Nadler of New York, the chairman of the House Judiciary Committee, told reporters.
White House officials believed that Mr. McGahn asserting his belief publicly would calm the president and help the administration push back on the episodes that Mr. Mueller detailed in the obstruction section of the report, said one of the people. Neither would be named describing private conversations involving the White House and spoke on condition of anonymity.
“We did not perceive it as any kind of threat or something sinister,” Mr. Burck said in a statement. “It was a request, professionally and cordially made.” A White House spokeswoman did not immediately return a message seeking comment.
White House officials asked Mr. McGahn again to put out a statement in the days after the report was released as Mr. Trump fumed about Mr. McGahn’s disclosures but he rebuffed the second request as well.
Around that time, the president’s lawyer, Rudolph W. Giuliani, began publicly attacking Mr. McGahn and questioned his credibility, saying that he had a bad memory. “It can’t be taken at face value,” Mr. Giuliani said of Mr. McGahn’s account one day after the report was released. “It could be the product of an inaccurate recollection or could be the product of something else.”
Mr. McGahn’s cooperation with Mr. Mueller played a key role in allowing the special counsel’s investigators to paint a picture in their report of a president determined to use his power atop the executive branch to protect himself from the Russia investigation.
The president’s lawyers are particularly concerned about two episodes that Mr. McGahn detailed to prosecutors. In one, Mr. Trump asked him to fire the special counsel but backed off after Mr. McGahn refused. After that episode was revealed, the president asked Mr. McGahn to create a White House document falsely rebutting his account. Mr. McGahn declined to go along but told Mr. Mueller about the encounters.
It makes no difference legally whether Mr. McGahn believes Mr. Trump obstructed justice. That is a determination made by prosecutors, not witnesses. But politically, such a statement could have been a powerful argument for Mr. Trump, who faces scrutiny from House Democrats about whether he obstructed justice and abused his power.
The Democratic-led House Judiciary Committee has subpoenaed Mr. McGahn to testify. But White House advisers have indicated they will try to block him from appearing before lawmakers, and Mr. Trump has said that there is no reason for Mr. McGahn to speak with congressional investigators because he had cooperated so extensively with Mr. Mueller’s team.
“I’ve had him testifying already for 30 hours and it’s really — so I don’t think I can let him and then tell everybody else you can’t,” Mr. Trump said in an interview with Fox News last week. “Especially him, because he was a counsel, so they’ve testified for many hours, all of them, many, many, many people. I can’t say, ‘Well, one can and the others can’t.’ I would say it’s done.”
Mr. McGahn left the White House last year but is still entangled with the president on matters related to the Mueller investigation. The White House instructed Mr. McGahn on Tuesday to not turn over documents he had to the House in response to a subpoena. Mr. McGahn followed the White House’s advice and is now waiting to see whether Democrats will hold him in contempt.