Tom Brenner / Reuters

In the 1999 Senate impeachment trial of President Bill Clinton, Senator Arlen Specter of Pennsylvania declined to vote guilty or not guilty, instead announcing his verdict as “not proven,” an old Scottish legal formulation. (Chief Justice William Rehnquist opted to record the vote as not guilty.)

Twenty years later, with impeachment again in the air, that phrase comes in handy. In Washington today, the House Intelligence Committee heard testimony in an inquiry into President Donald Trump’s actions in the Ukraine scandal. Across town, a jury found Trump’s old friend Roger Stone guilty on seven counts of federal crimes, related to a previous scandal involving Russian interference in the 2016 election.

Stone’s trial is a sort of postscript to Special Counsel Robert Mueller’s investigation into Russian interference. When Mueller released his report, some read it as an exoneration of Trump—it did not establish that his campaign colluded with Russia. Others understood it as a condemnation: Mueller strongly suggested that the president obstructed justice. The Stone trial suggests that a better way to summarize the alleged Trump-Russia connection might be: not proven.

Despite the extensive investigation by Mueller and the FBI, as well as inquiries by House and Senate committees, and now the record of the Stone trial, there’s a great deal that we simply don’t know about Trump and Russia, for two reasons.

First, Mueller approached his purview narrowly, acting as a prosecutor rather than as a fact-finder, and his report is long on vague formulations and short on specifics. He was at pains to show the high standard he had to meet to recommend criminal charges:

While the investigation identified numerous links between individuals with ties to the Russian government and individuals associated with the Trump Campaign, the evidence was not sufficient to support criminal charges. Among other things, the evidence was not sufficient to charge any Campaign official as an unregistered agent of the Russian government or other Russian principal. And our evidence about the June 9, 2016 meeting and WikiLeaks’s releases of hacked materials was not sufficient to charge a criminal campaign-finance violation. Further, the evidence was not sufficient to charge that any member of the Trump Campaign conspired with representatives of the Russian government to interfere in the 2016 election.

Second, we still don’t know the whole story, because the key players have kept their peace. Stone was convicted Friday of making false statements, obstruction, and witness tampering. He joins a list of people around Trump—including his first national security adviser, Michael Flynn; his deputy campaign chair, Rick Gates; his personal attorney, Michael Cohen; and his campaign adviser, George Papadopoulos—who have pleaded to or been convicted of similar crimes.

As for Trump, Mueller implied that several of his actions met the standard for obstructing justice, but the special counsel said Justice Department rules kept him from reaching a conclusion in the case of a sitting president. Trump refused an interview with the special counsel, and though he provided written answers to questions about Russia, he did not answer questions about obstruction or his campaign transition.

Taken together, this represents a wide-ranging conspiracy of silence that has blocked public understanding of the Trump campaign’s relationship with Russia.

Stone, a flamboyant and cartoonish character, has moved in the world of dirty-trick politics since his teens, when he worked for Richard Nixon’s infamous Committee to Re-elect the President. He was a longtime friend and partner of Paul Manafort, who managed Trump’s campaign in the summer of 2016, and who was convicted of several federal crimes last year. In 1980, Stone met Trump through their mutual friend Roy Cohn, who, as Michael Kinsley once wrote, was “innocent of a variety of federal crimes.” Starting in the late ’90s, Stone helped Trump feint at running for president.

All of this is to say that Stone and Trump were closely linked. Stone was also an adviser to Trump’s 2016 campaign in its early stages. He left the campaign, but remained in frequent contact with Trump; he also recommended Manafort to Trump as an aide.

In the Mueller report and in Stone’s trial, prosecutors presented evidence that showed Stone had tried to acquire emails that Russia had hacked from Democratic Party officials. Stone was apparently aware of WikiLeaks dumps before they arrived, forecasting that it would soon be the Hillary Clinton campaign chair John “Podesta’s time in the barrel.”

During the trial, Gates, who took a plea deal to cooperate with prosecutors, recounted a meeting with Trump on July 31, 2016. WikiLeaks had just released some emails damaging to the Clinton campaign. While Gates was present, Trump took a call from Stone. When the call ended, Gates testified, Trump told him that WikiLeaks would deliver “more information.”

That is at odds, sort of, with the president’s account. In his written answers to Mueller, Trump hedged about his conversations with Stone, claiming no memory (emphasis mine): “I do not recall being told during the campaign that Roger Stone or anyone associated with my campaign had discussions with any of the entities named in the question regarding the content or timing or release of hacked emails … I have no recollection of being told that Roger Stone, anyone acting as an intermediary for Roger Stone, or anyone associated with my campaign had communicated with WikiLeaks on October 7, 2016 … I spoke by telephone with Roger Stone from time to time during the campaign. I have no recollection of the specifics of any conversations I had with Mr. Stone between June 1, 2016, and November 8, 2016. I do not recall discussing WikiLeaks with him ...”

Prosecutors convinced jurors that Stone lied when he told Congress that he had no records of communications with his intermediary with WikiLeaks or with the Trump campaign about WikiLeaks. They offered a theory for why, too. “Roger Stone lied … because the truth looked bad for the Trump campaign and the truth looked bad for Donald Trump,” a federal prosecutor—Aaron Zelinsky, an alumnus of Mueller’s team—said in court. But why, exactly, did the truth look bad for Trump? What, exactly, was the truth?

Laws against witness tampering, false statements, and obstruction are intended to discourage criminals from impeding investigations to avoid punishment—and to create a fail-safe if they do so anyway, by ensuring that they are still punished for something. It looks like Stone will indeed be punished for something. But if his goal was to protect Trump—and obscure the truth—his obstruction worked.

Stone, who refused to cut a deal with prosecutors, may be angling for a pardon from the president. Pardons have not been forthcoming for Flynn or Manafort so far, but Trump did tweet in anger after the verdict, offering a nonsensical list of people he claimed should be in prison:

So they now convict Roger Stone of lying and want to jail him for many years to come. Well, what about Crooked Hillary, Comey, Strzok, Page, McCabe, Brennan, Clapper, Shifty Schiff, Ohr & Nellie, Steele & all of the others, including even Mueller himself? Didn’t they lie? A double standard like never seen before in the history of our Country?

Trump is right that there is a double standard, but it’s not what he thinks: It’s the standard that sends his aides to prison for putting roadblocks before federal prosecutors, even as the obstructor in chief skates free.

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