During her testimony in the House Intelligence Committee impeachment hearings last year, former National Security Council senior director Fiona Hill scolded U.S. representatives for believing and sometimes echoing Russian-inspired disinformation about alleged Ukrainian interference in our 2016 presidential election. She stated bluntly: “This is a fictional narrative that has been perpetrated and propagated by the Russian security services themselves.”

In a matter of days, U.S. senators will be exercising one of their most solemn constitutional duties as they take part in the second phase of the impeachment process. When they do so, they — and the rest of us — should take heed of Hill’s warning. By now it should be amply clear that Russian-style disinformation tactics, whether employed by Russians or Americans, represent a major threat to American democracy.

Russian President Vladimir Putin and his proxies deploy several methods of disinformation to strengthen their power and influence. The first is to deny facts. For instance, Putin initially denied that Russian soldiers had seized control of Crimea in February 2014, denies Russian involvement in the shoot-down of Malaysia Airlines Flight 17 in July 2014, and denies any Russian interference in the 2016 U.S. presidential election.

A second tactic is to deflect attention from the facts, also known as “whataboutism.” When criticized about Crimean annexing Crimea, Putin’s media shoot back, what about Kosovo? Or New Mexico? When criticized about civilian casualties from Russian military intervention in Syria, Kremlin defenders retort, what about Iraq, Vietnam or Hiroshima? When confronted with evidence of Russian meddling in U.S. elections, the Russian standard refrain is, you do it all the time.

A third practice is the dissemination of lies. Russian state media once asserted that President Barack Obama and former Islamic State leader Abu Bakr al-Baghdadi embraced the same ideology. I may be more sensitive than most about this tactic, because when I was serving as U.S. ambassador to Russia, Kremlin media outlets accused me of fomenting revolution against Putin’s regime; perhaps most disgustingly of all, a video was circulated suggesting I was a pedophile. When Putin met with President Trump in July 2018 in Helsinki, the Russian president again lied about me, claiming I had broken Russian law while working in the White House.

A cumulative effect of all these tactics is nihilistic debasement of the very concept of truth. Putin is not trying to win the argument; instead, his propaganda machine aims to convince that there is no truth, no right and wrong, or no data or evidence, only relativism, point of view and biased opinion.

We must not let these Kremlin-style tactics distort our public deliberations during the Senate trial.

First, we cannot allow denials to confuse our understanding of the facts of Trump’s withholding of military assistance to Ukraine. Trump denies he did anything wrong. We have heard extensive testimony from officials working in the Trump administration that clearly established the facts. Several current and former Trump administration officials, who have not yet testified, may know even more. Senators and the American people deserve to know them, too.

Second, senators and the media must avoid the temptations of whataboutism. At another time and place, a discussion may be warranted of the ethics of children of elected officials (Democrats and Republicans) being involved in businesses related to their parents’ public work. Congress also should conduct hearings about the Trump administration’s efforts to combat Ukrainian corruption. But neither of these issues has anything to do with impeachment.

Third, we must reject categorically falsehoods. The American cybersecurity company CrowdStrike did not cover up Ukrainian meddling in the 2016 presidential election; this is an entirely invented story. Former vice president Joe Biden was not freelancing on behalf of his son when implementing U.S. government policy — supported by the International Monetary Fund, the European Union, Republican senators, and the Ukrainian anti-corruption nongovernmental-organization community — to seek the ouster of corrupt Prosecutor General Viktor Shokin.

Indeed, because Shokin was not prosecuting corruption in Ukraine, his removal produced greater scrutiny, not less, of the now-infamous Burisma Holdings energy company on which Hunter Biden used to serve as a board member. As Shokin’s deputy, Vitaliy Kasko, reported, “There was no pressure from anyone from the U.S. to close cases against Zlochevsky [Burisma’s owner]. … It was shelved by Ukrainian prosecutors in 2014 and through 2015.” Trump’s own political appointee, former special envoy to Ukraine Kurt Volker, confirmed, “The allegations against Vice President Biden are self-serving and non-credible.”

Neutral reporting on false claims amplifies disinformation. Even those aiming to refute such falsehoods run the risk of spreading them more widely at the same time — a dynamic on which the purveyors of disinformation rely. At minimum, public figures and the media should resist the temptation to put false narratives at the center of their stories. Lies should be treated as such.

Putin controls the media and dominates public discourse in his country; it is for precisely that reason that he will never face impeachment. But the United States is a democracy. In our society, independent media and elected officials have the opportunity to access facts and data as a means toward more accountable government. The propagation of disinformation degrades this valuable attribute of democracy. Let’s not undermine this crucial principle of our republic — especially at this most serious moment in the life of our nation.

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