By Rachael Bade, Matt Zapotosky, Karoun Demirjian, Washington Post–

Former special counsel Robert S. Mueller III will testify to Congress in a public session next month about his investigation of Russia’s interference in the 2016 presidential campaign and possible obstruction of justice by President Trump, a reluctant witness long sought by House Democrats.

The House Judiciary and Intelligence committees, in an announcement late Tuesday, said that “pursuant to a subpoena,” Mueller has agreed to appear before both panels on July 17. Mueller, who oversaw the 22-month inquiry, is perhaps the one person lawmakers and the nation have been wanting to hear from the most.

“We are pleased that the American people will hear directly from Special Counsel Mueller. Our national security is being threatened and the American people deserve answers,” House Speaker Nancy Pelosi (D-Calif.), who has pushed back against calls to impeach Trump, said in a statement.

Mueller will testify in back-to-back hearings before the House Judiciary Committee, led by Chairman Jerrold Nadler (D-N.Y.), and the House Intelligence Committee, led by Chairman Adam B. Schiff (D-Calif.).

The long-awaited testimony comes as nearly 80 House Democrats have called for opening impeachment proceedings against Trump, arguing that he has ignored the Constitution that he took an oath to defend while repeatedly refusing to cooperate with congressional investigations.

Impeachment proponents hope Mueller’s testimony will increase public support for ousting the president. At the very least, his testimony is certain to provide the headline-grabbing, made-for-cable-television testimony that Democrats have been seeking since the 448-page redacted report was released April 18.

Still, some Democrats are already trying to temper expectations. Privately, some fear that Mueller’s much anticipated testimony won’t live up to the hype that has been built around him for months.

“I don’t want to set unrealistic expectations,” Schiff said in an interview after the announcement. “We want to hear what he has to say, and I think it’s very important for the American people to hear from him as well. But there are a great many other witnesses that the American people need to hear from in addition to Bob Mueller.”

Mueller spoke briefly in May, saying that he could neither clear nor accuse Trump of obstructing justice, leaving room for Congress to make that call and fueling impeachment demands among some Democrats. The remarks were his first public comments on the case since he concluded his investigation. Mueller said that if his office “had confidence that the president clearly did not commit a crime, we would have said so,” and he noted that the Constitution “requires a process other than the criminal justice system to formally accuse a sitting president of wrongdoing.”

Over the nearly two-year investigation, the special counsel charged 34 people, including 26 Russian nationals, and secured guilty pleas from seven, including several high-level Trump campaign and administration officials. The investigation concluded in March, and the following month the Justice Department released the office’s report documenting its work.

Robert Mueller wearing a suit and tie: In this March 24, 2019 photo, then-special counsel Robert Mueller walks past the White House, after attending St. John's Episcopal Church for morning services, in Washington.© Cliff Owen/AP In this March 24, 2019 photo, then-special counsel Robert Mueller walks past the White House, after attending St. John’s Episcopal Church for morning services, in Washington.The report said investigators found insufficient evidence to show a conspiracy between the Trump campaign and Russia to influence the election and reached no conclusion about whether Trump obstructed justice — despite laying out episodes of the president apparently seeking to stymie the investigation. Mueller’s team wrote that it was bound by Justice Department policy that forbids the indictment of a sitting president from deciding or alleging — even privately — that Trump had committed a crime.

The lawyer listed on the subpoena for Mueller, along with Mueller’s top assistants in the now-defunct special counsel’s office, did not immediately respond to phone and email messages. A Justice Department spokeswoman declined to comment.

Mueller is no longer a Justice Department employee, and after the special counsel’s office formally closed last month, he and his personal representatives had been negotiating directly with the committee, people familiar with the matter said. They spoke on the condition of anonymity to freely discuss private deliberations.

Mueller, a former FBI director, had preferred not to testify publicly, hoping his report would speak for itself, the people said.

But those who know him well said that it was virtually impossible that he would ignore or reject a subpoena.

Still, Mueller is unlikely to answer Democrats’ biggest question: whether he or his team thought there was sufficient evidence to charge Trump with obstruction, were he not president. The special counsel’s report said that making such a determination, even privately, would be inappropriate because of Justice Department policy that prevents the indictment of a sitting president, combined with concerns about alleging wrongdoing that would not be tested in court.

But even Mueller repeating aspects of his report in a public setting could be politically damaging for Trump — exposing the findings to sections of the country that may not be aware of them, and creating a televised spectacle.

Republicans made clear that the hearing will be a test for Mueller — although some of their GOP colleagues had also called for him to appear.

“I just think it’s more political theater,” said Rep. Mark Meadows (N.C.), a Trump ally who offered a warning: “Mr. Mueller better be prepared. I mean, there’s a lot more questions that Republicans have than Democrats.”

He added: “This is the Democrats trying to resurrect a Russia collusion narrative that the American people are tired of. And yet, Mr. Mueller has not been subject to cross examination. He will be now.”

Trump’s attorneys, meanwhile, began to call Mueller’s credibility into question and suggest that Mueller should be prepared to answer questions about anti-Trump text messages exchanged between two former FBI agents.

“The first thing he needs to answer is his own conflicts of interest,” Jay Sekulow, a Trump lawyer, said of Mueller on Fox News Channel’s “Hannity” on Tuesday night. He later added: “The whole report is incoherent.”

Sen. Lindsey O. Graham (R-S.C.) likewise argued that “I think it’ll blow up in their face.”

Democrats, meanwhile, welcomed the news. Rep. Ro Khanna (Calif.) thanked both chairmen on Twitter “for securing Mueller’s testimony.”

“To the naysayers who have doubted the effectiveness of our committee chairs, this shows measurable and real progress in our methodical and assertive approach in holding the President accountable,” he said.

rachael.bade@washpost.com

matt.zapotosky@washpost.com

karoun.demirjian@washpost.com

Mike DeBonis contributed to this report.