WASHINGTON — After all the swearing at, finally comes the swearing in. When Robert S. Mueller III takes the oath on Wednesday morning in the wood-paneled Room 2141 of the Rayburn House Office Building, he will answer questions for the first time since opening his special counsel investigation into President Trump and Russia more than two years ago.
But for all the anticipation, for all the fighting that it took to get to this day, many in Washington assume it will be more fizzle than sizzle. Mr. Mueller, the famously stoic prosecutor and reluctant witness, has vowed to adhere strictly to the words of his 448-page report and no more, making it unlikely that he will serve as the dramatic accuser Mr. Trump’s critics yearn to see.
“I don’t have high expectations for any additional substantive appreciation of Mr. Mueller’s investigation,” said former Senator Tom Daschle of South Dakota, who was the Democratic leader during the Senate impeachment trial of President Bill Clinton in 1999. “I think he’s going to stick to the script, and the Justice Department has told him to stick to the script, so I think it will be difficult for him to provide any more information.”
That is not to say it will be free of fireworks. Democrats will use Mr. Mueller to argue that Mr. Trump benefited from Russia’s help in the 2016 election even if investigators did not establish a criminal conspiracy and that his efforts to impede the investigation amounted to obstruction of justice even if Justice Department rules bar indictment of a sitting president. Republicans will grill the former special counsel to press their case that the entire investigation represented an illegitimate, partisan coup attempt even though Mr. Mueller himself is a lifelong Republican.
The resulting food fight could prove to be riveting television as cable and broadcast networks carry the proceedings live with back-to-back hearings before the House Judiciary and Intelligence Committees. And Mr. Mueller may be compelling simply by virtue of his just-the-facts credibility after two years of near silence. The real question, however, is whether it changes anyone’s mind in a highly polarized country that has already digested Mr. Mueller’s findings and dug in on its conflicting views of Mr. Trump and his guilt or innocence.
“I pay close attention, I am interested and I’ll watch him tomorrow morning, but I don’t have great expectations of some dramatic change or shift,” said Robert Dallek, the presidential historian who has written books on Richard M. Nixon, among others. “He’s not going to say, ‘This president is guilty as sin, you should impeach him.’ That’s not his style and it’s not his politics either.”
Kenneth M. Duberstein, who took over as President Ronald Reagan’s chief of staff after the Iran-contra scandal, said the hearing had become a sideshow. “I think the American people have moved on,” he said. “This is more for TV ratings. I would be shocked if Mueller would say something important that isn’t already out there. I don’t know a lot of people who are planning on listening in this town.”
Washington has seen plenty of dramatic hearings over the years, including John Dean testifying against his own president during the Watergate scandal that brought down Nixon and Oliver L. North in his Marine uniform explaining his role in Iran-contra and making himself into a hero of the right. For the first of his two hearings on Wednesday, Mr. Mueller will sit in the same chamber that Ken Starr presented his evidence against Mr. Clinton.
By the time Mr. Mueller takes his seat, however, he will be speaking a full four months and two days after delivering his report to the Justice Department — or after 2,191 presidential tweets as of 8 p.m. Tuesday, to use another measure. By now, whether they have actually read it or not, many Americans and their representatives in Congress have already settled on what they think Mr. Mueller’s findings mean.
The delay in his testimony and the ability of Attorney General William P. Barr to frame the results of his investigation on terms most favorable to Mr. Trump, who appointed him, have cemented a political reality long before Mr. Mueller explained his conclusions in any depth. The only time he has spoken about the investigation in public before now was a nine-minute statement in May when he took no questions.
That by itself makes his appearance important. Ken Gormley, the president of Duquesne University and author of books on Archibald Cox, the Watergate prosecutor, and the battle between Mr. Clinton and Mr. Starr, said no special counsel has been in this position. Mr. Cox resisted testifying to Congress because he was still contemplating criminal charges while Mr. Starr operated under a different law that required him to report what he considered impeachable offenses to Congress.
Mr. Mueller, who acted as a Justice Department subordinate, had no explicit authority to recommend impeachment, a function of Congress. And so many will scrutinize his words carefully to see if they add fuel to the drive by some Democrats to impeach Mr. Trump, a drive that gained the support of the N.A.A.C.P. on Tuesday.
“To me, it’s as dramatic as John Dean testifying,” Mr. Gormley said of Mr. Mueller’s appearance. “It really is unprecedented. We’ve never had this kind of situation.”
For their part, Republicans on Tuesday took on their best nothing-to-see-here demeanor, dutifully repeating the party’s Americans-have-moved-on talking points.
“We’ve already heard from him,” said Senator Mitch McConnell, Republican of Kentucky and the majority leader. “I don’t know how many times we want to see this movie again, but I think the American people have moved on past this.”
Asked how much attention voters would pay, Senator John Kennedy, Republican of Louisiana, predicted “little to none,” adding: “I think the American people have moved on. I think the issue’s dead as four o’clock. I think people have already drawn their own conclusions.”
While playing down expectations, Democrats were still hoping for a splash. Judiciary Committee Democrats conducted a mock hearing on Tuesday, with Norman L. Eisen, one of their lawyers, playing Mr. Mueller and another aide playing Representative Jim Jordan, Republican of Ohio. Party leaders separately coached their members on how to talk about Mr. Mueller’s testimony to make sure they can capitalize on any momentum he provides.
Aides to Speaker Nancy Pelosi circulated a six-page briefing packet, titled, “Exposing the Truth,” charging the Trump administration with “unparalleled abuses of power and corruption while hiding the truth from the American public.” It urged Democrats to talk not just about Mr. Mueller’s findings but also legislative actions the Democrat-controlled House has taken to harden the 2020 elections against foreign interference.
But it also smacked of a field test of something more ambitious, a 2020 campaign message meant to sow doubts about Mr. Trump’s loyalties and actions. And if Washington veterans were jaded about the hearings, Democrats were gambling that it would take only one or two viral video clips to engage the public.
A completely unscientific survey of out-of-town diners in a House cafeteria on Tuesday suggested the potential. Most were in Washington to lobby lawmakers, meaning they keep a closer eye on events in the Capitol than many Americans.
Kia Birkenbuel, 60, a disability rights advocate from Montana, said she had read Mr. Mueller’s report and was more concerned with its findings about Russian interference than its evidence that the president may have obstructed justice. “I’m excited to hear what he has to say,” she said, “even if he has to keep within the boundaries of the report.”
At another table, Gabby Saunders, 22, an advocate for wildlife conservation from Utah, said she had read most of the report — and what she had not read, she listened to on audio. She called the coming testimony “the pinnacle of what we’ve been waiting for,” adding: “I’m from Utah. This is my second time being on the Hill. If I could see that live, it would be extraordinary.”