Shutterstock / Billion Photos / Arsh Raziuddin / The Atlantic

The House vote to impeach the president cues up a Senate trial on the charges, and the Republican leadership appears determined to prevent key fact witnesses close to the president from testifying. Majority Leader Mitch McConnell has called any witness list that House impeachment managers and the president’s defenders might negotiate “mutually assured destruction.” Resistance to live testimony arises because, while dishonesty and disinformation have become regular features of America’s national discourse, witnesses under oath cannot lie with impunity. Should they commit perjury, they may find that “court is one of those places where facts still matter,” as Judge Amy Berman Jackson put it to Paul Manafort at his recent sentencing for, among other things, lying to investigators.

A dozen administration officials defied House subpoenas for testimony or documents relevant to the impeachment proceedings. Despite Senate Democrats’ request for witnesses at the trial, there now seems only the slimmest chance—perhaps as the result of some procedural vote or a ruling by Chief Justice Roberts while he presides over the trial—that John Bolton, Mick Mulvaney, or others will finally take the stand. Some of the potential witnesses have already asserted facts and staked out positions publicly. But there is a crucial difference between cable-news interviews, press conferences, and tweets on the one hand, and statements under oath on the other.

Should these witnesses testify, they can resist certain questions—for example by invoking executive privilege or their own Fifth Amendment rights—and they would surely insert “do not recall”s into the record, but they would face consequences for lying. The president often characterizes his public comments on pending investigations as “freedom of speech” or “fighting back,” but his aides have no First Amendment right to lie under oath, and perjury is never excused by self-defense. As the Supreme Court stated in the Bryson case 50 years ago: “Our legal system provides methods for challenging the Government’s right to ask questions—lying is not one of them.”

In many religious and moral traditions, bearing false witness constitutes the most serious form of deception and occasions the most dire punishment. Even if the solemn nature of an oath no longer instills fear of eternal damnation, breaking that oath does warrant a felony charge. Among the 4,000-plus federal crimes, at least 300 address various forms of deception. Perjury—willfully making a false statement under oath about facts material to an official proceeding—is the most significant of the federal “dishonesty offenses.” Perjury goes way back: In legal texts from the ancient world and medieval codes, it was punishable by death. In the 16th-century common law that is the precedent for America’s criminal statute, perjury was declared “infamous and detestable.” Since the First Congress, in 1790, lying under oath has been proscribed under federal law, and all 50 states now have statutes criminalizing perjury.

The elements required to prove perjury are stringent and specific. Under Title 18, United States Code, Section 1621, prosecutors must demonstrate that the sworn statement is false, that the lie is willful and deliberate, and that the statement could influence the proceeding. Cases can be difficult to prosecute and prove, because perjury requires clear and direct questions and brazenly untrue responses. The law does not prohibit trivial falsehoods or carelessness, statements that are misleading but “literally true,” or statements that are incomplete and “merely evasive.”

The general perjury statute covers false evidence presented to tribunals other than courts that act with the authority of law, including Congress. Should witnesses lie to Congress, they could later—up to five years later, given the statute of limitations—face a criminal indictment in court. Impeachment proceedings have intersected with perjury charges before. Both President Richard Nixon’s chief of staff, H. R. Haldeman, and his attorney general, John Mitchell, served time in prison for perjury committed before the Senate Watergate Committee. And one of the articles of impeachment against President Bill Clinton arose from his testimony to the grand jury and sworn deposition in Paula Jones’s civil suit.

Indeed, at the very moment that the former ambassador to Ukraine was testifying before the House Intelligence Committee last month, Roger Stone was convicted of lying to the same committee under oath in 2017. At the trial, his defense lawyer argued that the question boiled down to whether Stone’s lies to the committee about his contacts with WikiLeaks on behalf of the Trump campaign made any difference. “So what?” he asked the jurors in summation. And they answered, convicting Stone on all seven counts of the indictment. One of the Stone jurors recently published a defense of the verdict, writing: “At a time when so much of our public discourse is based on deception or just lies, it is more important than ever that we still have places where the truth can be presented, examined, and discerned.”

This is the same assertion judges and prosecutors have made time and again when describing the harm of perjury. The Supreme Court has called it a “pollution,” an “egregious offense,” and an “obvious and flagrant affront to the basic concepts of judicial proceedings.” In the rapper Lil’ Kim’s 2005 trial involving perjury about a shooting she witnessed, the judge admonished her: “You tried to charm and fake [the jurors] out. They saw you lie to them. I saw you lie. It was an insult to the court and to the system.” Special Counsel Patrick Fitzgerald made similar comments after Scooter Libby’s 2007 conviction for lying to a grand jury about the unauthorized disclosure of classified information (for which he recently received a presidential pardon). “We cannot tolerate perjury,” he said. “The truth is what drives our judicial system. If people don’t come forward and tell the truth, we have no hope of making the judicial system work.”

Perjury sanctions not only preserve the integrity of sworn testimony but also affect the behavior of people who encounter the justice system. Consider how questioning under oath tends to quiet even the loudest conspiracy theorists. Infowars founder Alex Jones, who faces several lawsuits by families whose children were killed in the mass shooting at Sandy Hook Elementary School in Newtown, Connecticut, in 2012, withered during a detailed, methodical deposition about the sources of his claims that the murders were all a hoax. At one point, Jones was reduced to arguing: “We have a right in this country to question things!” The lawyer countered that he was not asking about what Jones had a “right to do,” just about “what he did.” Truthful testimony does not turn on what people “believe” or “think,” but rather requires precision about how they acted, what they saw and said, and whether they are reporting these things forthrightly.

When the law compels sworn testimony, that mechanism of accountability protects the public. Absent an applicable privilege, according to a centuries-old maxim, the public has a right to “every man’s evidence.” And evidence is more valuable now than ever. Given not only the degradation of truth in politics but also the disregard for science and even the corrosion of language, the current crisis of empiricism is a popular book and magazine topic. American historians write of the “madness” of the declining allegiance to democratic norms, and it is commonplace to invoke Orwell. And the steadfast civil servants who stepped forward to testify in recent weeks appear heroic for “simply relating the facts” and thereby speaking “truth to nonsense.”

According to a recent Rand report, Americans have become more distrustful of experts and other sources of information. Salman Rushdie—a novelist who once embraced theories of literary criticism questioning the existence of any objective truths—recently wrote that now “we need to rebuild our readers’ belief in argument from factual evidence” and reconstruct “an understanding about what is real.” That feels essential to any repair of civic life through the political process, but even engaged voters report being overwhelmed by partisan news and social-media distortions. Some do not know what to believe and so believe nothing. Journalists have taken to counting how many lies come from the current administration—15,413 per the latest check of The Washington Post’s tally. Effectively countering the volume and velocity of falsehoods with information is a mighty struggle. Even painstaking (and nonpartisan) special-counsel and inspector-general investigations immediately encounter assertions that their reports contain conclusions contrary to what they actually found. At some point, the American body politic needs to start identifying and relying on facts again.

The best places to accomplish that remain the nation’s legal institutions, where logic, reason, and evidence still tend to prevail. The courts, in Alexander Hamilton's conception, were “the least dangerous branch” of the federal government. But even though they do not control “either the sword or the purse,” they do render “judgment.” And in the months to come, such judgment will send strong signals—requiring testimony, punishing lies, and perhaps restoring shared reference points. It provides some comfort that perjury sanctions retain the power to deter falsehoods and partisan spin. And that’s why a lot of Americans are waiting anxiously for this proverbial “day in court” to come.

This story is part of the project “The Battle for the Constitution,” in partnership with the National Constitution Center.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.