For decades, Roger J. Stone Jr. played politics as a kind of performance art, starring himself as a professional lord of mischief, as a friend once called him. He tossed bombs and spun tales from the political periphery with no real reckoning, burnishing a reputation as a dirty trickster.
On Friday morning, a reckoning arrived, the consequence of his efforts to sabotage a congressional investigation that threatened his longtime friend President Trump.
Mr. Stone, 67, was convicted in federal court of seven felonies for obstructing the congressional inquiry, lying to investigators under oath and trying to block the testimony of a witness whose account would have exposed his lies. Jurors deliberated for a little over seven hours before convicting him on all counts. Together, the charges carry a maximum prison term of 50 years.
In a last-minute bid for salvation, prosecutors said, Mr. Stone appealed to Mr. Trump for a pardon on Thursday, using a right-wing conspiracy theorist who runs the website Infowars as his proxy. Mr. Trump attacked the guilty verdict against Mr. Stone in a tweet on Friday but made no mention of a pardon.
To some friends, Mr. Stone’s fatal flaw was that he did not know when the time for gamesmanship was over. “The only thing worse than being talked about is not being talked about,” he liked to say. But that mantra seemed to ring hollow as Mr. Stone, forced to stand in silence, heard a courtroom deputy read the word “guilty” seven times.
The impeachment inquiry underway nearby on Capitol Hill overshadowed news of the verdict, but it was nonetheless another setback for the president. Mr. Stone is the sixth former Trump aide to be convicted in cases stemming from the investigation by the special counsel, Robert S. Mueller III, into Russia’s interference in the 2016 election.
And the trial revived the saga of Russia’s efforts to bolster Mr. Trump’s chances of winning the White House just as House impeachment investigators are scrutinizing how Mr. Trump pressured another government, Ukraine, to help with his 2020 re-election chances.
Prosecutors said Mr. Stone tried to thwart the work of the House Intelligence Committee because the truth would have “looked terrible” for both Mr. Trump and his campaign. They built their case over the past week with testimony from a friend of Mr. Stone and two former Trump campaign officials: Rick Gates, the deputy campaign chairman, and Stephen K. Bannon, who led the campaign through its final three months and served as a White House strategist early in the administration.
Hundreds of exhibits that exposed Mr. Stone’s disdain for congressional and criminal investigators buttressed the testimony.
The evidence showed that in the months before the 2016 election, Mr. Stone strove to obtain emails that Russia had stolen from Democratic computers and funneled to WikiLeaks, which released them at strategic moments timed to damage Hillary Clinton, Mr. Trump’s Democratic opponent. “Every chance he got,” prosecutors said, Mr. Stone briefed the Trump campaign about whatever he had picked up about WikiLeaks’ plans.
But he told the House committee in September 2017 that he never described to anyone involved in the Trump campaign his conversations with an intermediary to WikiLeaks.
The trial called into question Mr. Trump’s own answers to queries from Mr. Mueller. The president, who refused to be interviewed and agreed to respond to questions only in writing, said he could not recall the specifics of any of 21 conversations he had with Mr. Stone in the six months before the election.
In one of the trial’s most revealing moments, Mr. Gates recounted a July 31, 2016, phone call between Mr. Stone and Mr. Trump, just days after WikiLeaks had released a trove of emails embarrassing the Clinton campaign. As soon as he hung up with Mr. Stone, Mr. Gates testified, Mr. Trump declared that “more information” was coming, an apparent reference to future releases from WikiLeaks that would rattle his political rival.
Within minutes of the verdict, Mr. Trump protested on Twitter that it was unfair. “So they now convict Roger Stone of lying and want to jail him for many years to come,” Mr. Trump wrote, though his own administration’s Justice Department prosecuted Mr. Stone.
He then listed the names of nearly a dozen favorite targets of his ire, including Mrs. Clinton, Mr. Mueller, the former F.B.I. director James B. Comey and Representative Adam B. Schiff, who heads the House Intelligence Committee. “Didn’t they lie?” he tweeted, and then added: “A double standard like never seen before in the history of our Country?”
Mr. Stone joins a notable list of former Trump aides who either pleaded guilty or were convicted of federal crimes in cases stemming from Mr. Mueller’s work. It includes Mr. Gates; Michael T. Flynn, the former national security adviser; Michael D. Cohen, the president’s longtime fixer; George Papadopoulos, a former Trump campaign aide; and Paul Manafort, Mr. Trump’s former campaign chairman and Mr. Stone’s onetime partner in a political consulting firm.
Although the counts against him add up to 50 years, the punishment for Mr. Stone, who had no previous criminal record, will almost certainly be far lighter. On the other hand, his multiple run-ins earlier this year with Judge Amy Berman Jackson, who will sentence him on Feb. 6, could work against him. After a series of infractions, including posting a photo of the judge with an image of cross-hairs next to her head on Instagram in February, she banned him from social media.
After the verdict, prosecutors asked Judge Jackson to put Mr. Stone behind bars, arguing that he had defied her once again by passing the message to Infowars’ Alex Jones, saying, “I appeal to the president to pardon me.” But the judge said it was not entirely clear whether Mr. Stone had disobeyed her and noted that he had complied with her orders in recent months.
Mr. Stone’s lawyers argued that the prosecution’s case was based on speculation and false assumptions about Mr. Stone’s motives. Mr. Stone had no reason to lie in order to protect the president nearly a year after Mr. Trump had won the election, Bruce S. Rogow, the lead defense lawyer, told jurors.
Mr. Stone had simply confined his answers to the strict parameters of the committee’s inquiry, he argued. He also said that even though Mr. Stone had portrayed himself to the campaign as Mr. Trump’s link to WikiLeaks, that was just more of Mr. Stone’s typical braggadocio.
Much of the trial revolved around relationship between Mr. Stone and Randy Credico, a New York radio host and comedian. The charge that Mr. Stone had tried to block Mr. Credico from testifying to the House committee was the most serious one he faced, carrying a maximum penalty of 20 years. Mr. Credico ultimately asserted his Fifth Amendment rights against self-incrimination and refused to testify to the House committee.
He testified at the trial that despite the fact he repeatedly urged Mr. Stone to tell the truth, he falsely identified him to congressional investigators as his intermediary with Julian Assange, the founder of WikiLeaks. Previously in their tortured 17-year friendship, he said, Mr. Stone had treated him as his “patsy.”
In an effort to ward off Mr. Credico’s congressional testimony, the evidence showed, Mr. Stone alternately flattered, bullied and threatened the radio host. At one point, Mr. Stone pretended that he had written a letter to the House committee characterizing Mr. Credico as highly talented and successful.
At other points, he urged Mr. Credico to “Do a Frank Pentangeli,” referring to a character in the movie “The Godfather: Part II” who gave false testimony during a Senate hearing on organized crime. Borrowing a quote from Richard M. Nixon to a top aide during the Watergate cover-up, Mr. Stone texted Mr. Credico in late 2017: “Stonewall it. Plead the fifth. Anything to save the plan.”
If he refused to go along, Mr. Credico testified, Mr. Stone promised to retaliate against him and Margaret Ratner Kunstler, a lawyer for Mr. Assange and one of Mr. Credico’s dearest friends. Prosecutors described Ms. Kunstler as a particularly effective “pressure point” with Mr. Credico, an unmarried man with no children and a 34-year history of alcohol abuse.
One of Mr. Stone’s most blatant deceptions, prosecutors said, was hiding records of his communications. He told congressional investigators that he and Mr. Credico only spoke on the phone, because Mr. Credico “was not an email guy.”
In fact, in the year and a half before Mr. Stone testified, he and Mr. Credico exchanged more than 1,500 emails and text messages, including 72 texts alone on the day of Mr. Stone’s congressional testimony. Because Mr. Stone misled the committee, prosecutors said, investigators failed to pursue promising leads and arrived at inaccurate conclusions in its final report on Russia’s election interference.
Mr. Credico tried for months to warn Mr. Stone that his lies would catch up to him. Among Mr. Stone’s responses: “Nice try.” “Meaningless.” “So what.”