WASHINGTON — Just as a rapidly spreading impeachment investigation has riveted attention on whether President Trump tried to pressure a foreign ally to bolster his 2020 campaign, a criminal trial set to open in Washington is refocusing attention on the last presidential election, and Russia’s interference in it.
The trial of Roger J. Stone Jr., a former Trump campaign adviser and longtime friend of the president, will begin Tuesday morning with jury selection in the federal courthouse for the District of Columbia. The case is one of the last outstanding criminal prosecutions stemming from the nearly two-year inquiry by the special counsel, Robert S. Mueller III, that ended in the spring.
Mr. Stone, one of a half-dozen former Trump aides who were indicted, faces charges that he lied to Congress, obstructed justice and tried to tamper with a witness.
The trial, expected to last about two weeks, may be lively. A swashbuckling and abrasive political trickster for decades, Mr. Stone, 67, has been repeatedly rebuked for flouting the prohibitions on pretrial publicity set by Judge Amy Berman Jackson, who is overseeing the case. At one point, she complained that trying to govern Mr. Stone’s behavior was like supervising a middle schooler.
One witness expected to testify against Mr. Stone is nearly as flamboyant and eccentric as he is. Randy Credico, a New York radio personality and comedian, brought a tiny white dog to his grand jury appearance as a “comfort” animal.
Mr. Credico is expected to testify about whether Mr. Stone pressured him to lie to the House Intelligence Committee about what he knew about efforts to contact WikiLeaks on behalf of the Trump campaign. Mr. Stone is charged with trying to tamper with Mr. Credico’s testimony and with deceiving the same committee himself, charges that carry a maximum penalty of 20 years.
Mr. Mueller’s investigation found insufficient evidence to charge anyone tied to the Trump campaign with criminally conspiring with WikiLeaks or the Russians to damage the campaign of Hillary Clinton. But as documents released last week by the Justice Department underscore, Trump campaign aides were elated when WikiLeaks began publishing emails that the Russians stole from Democrats.
The eagerness of Mr. Trump’s advisers to accept assistance from Russia and from WikiLeaks in 2016 has a parallel in the current scandal that imperils Mr. Trump’s presidency.
The impeachment inquiry in the House is focused on Mr. Trump’s efforts to pressure Ukraine to announce criminal investigations that would help him politically. Mr. Trump wanted Volodymyr Zelensky, who was elected in the spring as president of Ukraine, to open an inquiry into unfounded allegations that former Vice President Joseph R. Biden Jr., one of his Democratic rivals in the 2020 election, quashed an investigation of a Ukrainian company to protect his son Hunter Biden, who sat on the board.
The president also wanted Mr. Zelensky to proclaim that he was investigating a conspiracy theory that Ukraine had tried to damage his chances of winning the White House in 2016. He has complained that Ukraine played some role in triggering the Mueller investigation.
Mr. Stone’s trial could shed new light on whether Mr. Trump was personally aware of WikiLeaks’ strategy to release thousands of emails that damaged the Clinton campaign at key moments in the race.
In written answers to questions from Mr. Mueller, Mr. Trump said he did not recall any communications with Mr. Stone in the six months preceding the 2016 election.
But Mr. Trump’s deputy campaign chairman, Rick Gates, told the F.B.I. that in the summer of 2016, as he rode in a car with Mr. Trump to a New York airport, Mr. Trump took a call, then informed him that WikiLeaks planned more releases. While investigators have never identified the caller, former campaign aides have said it was most likely Mr. Stone.
Throughout the campaign, Mr. Stone presented himself to Trump campaign officials as a conduit for inside information from WikiLeaks. One former campaign official told the F.B.I. that Mr. Stone not only seemed to predict WikiLeaks’ actions, but that he also took credit for the timing of disclosures.
But Mr. Stone later insisted that he never had any inside information from WikiLeaks, and his claims were simply “posture, bluff and hype.”
Prosecutors claim that in September 2017, Mr. Stone lied to the House committee both about his communications with the Trump campaign and about his efforts to obtain information from Julian Assange, the founder of WikiLeaks.
They also claim that he tried to prevent Mr. Credico from testifying at all. Texts show that Mr. Stone at one point threatened to take his dog Bianca. He also urged Mr. Credico to “stonewall it” and “plead the Fifth.”
It is unclear whether Mr. Stone plans to testify in his own defense. Mr. Stone, who has steadfastly proclaimed his innocence, unexpectedly took the stand during a pretrial hearing in February. He asked the judge then not to penalize him for posting a photograph of her, with an image of cross-hairs in the corner by her head, on Instagram.
Judge Jackson eventually ordered Mr. Stone off all major social media platforms, saying he had used them to attack Mr. Mueller’s investigation in violation of her orders.