Donald Trump spent two hours alone with Vladimir Putin in Helsinki in July and we still have no idea what was specifically said or agreed between two of the most powerful men in the world. (Only two interpreters, bound to silence, were present.)

How much does this matter?

Quite a lot, probably. First off, there are new concerns about Trump’s continuing susceptibility to talking points that can have only one source – Russian propaganda. More of this later. Second, it belongs in a long trail of events that have either deliberately left serious blanks in the historical record or delayed by many years discovery of the truth.

We live in a moment in America when the discovery of information is in daily hand-to-hand combat with the deliberate suppression of information. For the second time in recent history the fate of a presidency might well rest on the unhindered discovery and exposure of essential evidence. Nothing is as central to the health of a democracy as overcoming a cover-up.

In 1974 the evidence that proved fatal to Richard Nixon’s presidency was all on tape—the White House tapes that recorded the president’s unguarded conversations with aides as they engineered the Watergate cover-up.

But one section of those White House tapes still remains undisclosed. Nixon’s secretary, Rose Mary Woods, removed eighteen and a half minutes of a key recording of conversations between Nixon and his chief of staff, H.R Halderman between March and April 1973. According to her this was inadvertent—and covered only five minutes of the taping.

Experts who examined the equipment in 1974 decided that several portions of several conversations had been removed, adding up to eighteen and a half minutes. In 2009 new technology was employed to try again, but failed and Nixon and Haldeman took the secret of what was said to their graves. Some historians believe that Nixon himself could have erased the tapes.

As it turned out, that erasure was frustrating but not decisive. The smoking gun evidence survived amply in other tapes that were seized by prosecutors before they could be destroyed.

A similarly lingering mystery envelops the activity of a special energy task force set up by Vice President Dick Cheney in January 2001.

Cheney told President George W. Bush that the purpose was to develop “a national energy policy designed to help to bring together business, government, local communities and citizens to promote dependable, affordable and environmentally sound energy for the future.”

That was a laughably laudable version of what Cheney was apparently really up to. The task force was supposed to be confined to government officials. Then it turned out that meetings had been attended by waves of energy industry leaders and lobbyists. A report was issued in May 2001. It downgraded the importance of renewable energy in favor of an aggressive expansion of existing energy sources—including the need to build new pipelines, open up new regions for drilling and review the security of foreign sources of oil.

Within months of that report appearing Cheney was directing the response to the 9/11 attacks. He was instrumental in persuading Bush that, rather than concentrating on pursuing Osama bin Laden, the perpetrator, the U.S. should instead give priority to invading Iraq—one of the richest sources of oil in the Middle East. No reliable accounting of the task force’s discussions on foreign oil fields has ever been provided.

When Cheney left his job as CEO of Halliburton to join the Bush administration he received a severance settlement worth $36 million. Halliburton subsequently earned $39 billion as a contractor supporting US troops in Iraq and returning the Iraq oil fields to production.

When it comes to having a record of what presidents discuss with other foreign leaders there is a precedent, of sorts, for Trump in Helsinki, from the last years of the Cold War.

In 1985, during a summit meeting in Geneva with the Soviet leader, Mikhail Gorbachev, President Ronald Reagan spent over an hour with Gorbachev with only interpreters present and later took a walk with Gorbachev to a pool house where they talked for another 44 minutes without anyone else present.

The two leaders, both fearful of nuclear war, were negotiating a new nuclear arms treaty, part of complex talks that had been going on for years. Reagan was not required to have mastery of the technical details, and nothing made his officials more nervous than the idea that, left alone with Gorbachev, he might be seriously outplayed.

They needn’t have worried. Reagan had become mesmerized by the prospect of a new super-weapon, dubbed “Star Wars,” that could intercept incoming missiles in space, even though it was way beyond what was possible, and Reagan had no intention of abandoning his fantasy. He saw it as a way of forcing the total abolition of nuclear weapons.

That never happened, of course. But what the two men had actually discussed in the pool house remained unknown until 2015, when Reagan’s Secretary of State, George Shultz, revealed that Reagan had asked Gorbachev how he would respond if America were suddenly attacked by aliens from outer space. “Would you help us?” Reagan asked. “No doubt about it” replied Gorbachev.

That might seem anticlimactic and comical but Reagan had been far more effective than Shultz knew at the time: his conviction that Star Wars was a reality spooked the Russians into the same belief and made them more eager to make concessions.

“ At the end of the meeting Heydrich insisted that there should be no verbatim record. Instead, a summary was written and copies of it limited to the 30 participants, known as the Wannsee Protocols. Those copies disappeared at the end of the war—or so it was thought. ”

Across the pond, British historians have a tougher time ferreting out the truth about deals that have serious consequences. Politicians can take cover under rules that usually guarantee that really embarrassing lapses won’t emerge during their lifetime, because the release of highly sensitive documents is embargoed for 50 years—or, in some cases, are “lost” during their lifetime.

That was the case in 1956 when British, French and Israeli officials colluded in a secret plan to get rid of Egypt’s leader, General Gamal Abdel Nasser, who had just ended British and French control of the Suez Canal. Basically the idea was that Israel would attack Egypt, and then France and Britain would intervene under the fictional pretext that they were ending the conflict and, having done so, would remove Nasser.

From the start the plan was driven by the hubris of Britain and France, whose leaders seriously underestimated the regional support for Nasser. He was determined to restore true independence to Egypt and become the figurehead of Arab nationalism.

The Israelis were the only militarily competent partners in a scheme that was hobbled by mutual distrust. International laws were about to be violated. Britain kept its most important ally, America, in the dark.

The meeting that set the attack in motion took place in a villa outside Paris. Israeli leaders arrived under cover after a flight in a French military transport. Two people referred to only as “the responsible minister and an official” hopped over from London, the minister arranging an appearance in the House of Commons immediately beforehand intended to indicate that he never left London. The two of them were in France for little more than an hour.

At the end of the meeting the principals agreed that none of them would reveal in their lifetimes what they had discussed. In effect, the meeting never happened.

Ten years later one historian, trying to establish who the British minister was, heard from a French source that he resembled “an old-fashioned family lawyer.” That was clue enough. He was the British Foreign Secretary, Selwyn Lloyd, a man hopelessly out of his depth in such a Machiavellian scheme.

The operation was a military debacle and a diplomatic disaster. Instead of removing Nasser it consolidated his hold on power. Britain and France were finished as colonial powers. Anthony Eden, the prime minister who had waited so long as Winston Churchill’s understudy, never recovered his reputation. The lasting lesson was that shit happens more easily when momentous decisions are taken invisibly.

But beyond any doubt the single most infamous meeting that never happened took place in another villa, this time on the shore of Lake Wannsee, near Berlin, on January 20, 1942.

The meeting was called by Reinhard Heydrich, the head of Nazi Germany’s SS Security Office. It was attended by 30 people and lasted only 90 minutes but it set in motion the whole apparatus designed to exterminate Europe’s Jews. The two principal architects of the Holocaust, Adolf Hitler and Heinrich Himmler, were not present—Heydrich was their instrument, the man who industrialized the genocide.

Heydrich directed: “In the course of the practical implementation of the final solution, Europe will be combed from West to East.”

As one of the key historians of the Holocaust, Martin Gilbert, wrote, “What had hitherto been tentative, fragmentary and spasmodic was to become formal, comprehensive and efficient.”

At the end of the meeting Heydrich insisted that there should be no verbatim record. Instead, a summary was written and copies of it limited to the 30 participants, known as the Wannsee Protocols. Those copies disappeared at the end of the war—or so it was thought. Then, in 1947, an American prosecutor working for the Nuremberg Tribunal on Nazi war crimes, Robert Kempner, found one copy in the German foreign office archives.

By any measure this was one of the most essential document discoveries related to the Holocaust. It left no doubt that the atrocity began at the top and was executed by a terrifying bureaucratic machine. When Heydrich’s sidekick Adolf Eichmann was captured in Argentina in 1960 by an Israeli task force and brought to trial in Israel he described that machine in remorseless detail, as though all its evil had been subsumed in the robotic obedience needed to carry out the assigned task.

It would be nice to think that in the end history will always be able to retrieve the deliberately created gaps in the record, whether major or relatively minor—that truth will out simply because it has an ineluctable quality. But surely, given the examples above, history requires relentless pursuit to make that happen.

Helsinki’s peculiar lacuna may turn out to be relatively minor, but unless we know what was really said we can’t be sure.

Putin is a master of mind games learned as a Soviet intelligence agent. Trump, with his blend of narcissism and ignorance, presents a soft target for these games. He is an empty vessel into which ideas can easily be seeded. How often this happens and by what means are worrying questions, heightened this week when Rachel Maddow showed three examples of either Trump or Trump people suddenly spouting talking points that were so incongruous that they could come from only one place—propaganda created by Russian intelligence.

The first came just weeks after Trump’s inauguration. The Associated Press reported that Trump national security aides were concerned that Poland was preparing to invade Belarus. The only people spreading this bizarre notion were Putin’s propagandists. (At that time General Mike Flynn was the national security adviser, an obvious stovepipe for the Putin line.)

The second, in the summer of 2018, was when—out of nowhere—Trump, talking on Fox News, blurted out that the people of the small Balkan state of Montenegro were “very aggressive” and could start World War III. As Maddow pointed out, that was the Putin line at the time of elections in Montenegro in 2017 when a Russian intelligence plot to take power in Montenegro was exposed and foiled.

The third example just happened—during the course of the so-called meeting of the Trump cabinet when cameras were allowed to cover the whole 90 minutes. It was not so much a meeting as a monologue in which Trump combined salutes to his own towering genius with strange assertions, the strangest being that the Soviet invasion of Afghanistan in 1979 had been justified because “terrorists from there were going into Russia.”

Until now Russian historians had concluded that the Afghan invasion was a mistake and one that ended with an ignominious retreat. But here was Trump saying “They were right to be there.”

Maddow pointed out that this is Putin’s latest revisionist line—both his party and the communists are rewriting Russian history using the falsehood that it was a move to stop terrorism.

The former U.S. ambassador to Russia, Michael McFaul, reviewing these three events, told Maddow: “It is striking how Trump does pick up these strange ideas from Putin, there is a pattern here.”

After their Helsinki meeting, Trump looked like a man in thrall to Putin. Asked if he still believed that Russia had interfered in the 2016 election, he said “I have great confidence in my intelligence people, but I will tell you that President Putin was extremely strong and powerful in his denial today. He said it’s not Russia. I will say this. I don’t see any reason why it would be….”

Later, after even House Speaker Paul Ryan rebuked Trump for the remarks, he attempted to rewrite what was already on the record by saying he had intended to say “I don’t see any reason why it would not be”—a tautology that convinced nobody.

Syria was one of the subjects Trump discussed with Putin. At the press conference following the meeting Putin said that Syria could be “the first showcase example” of successful joint work. Trump’s impetuous decision last month to pull out of Syria came after a phone call with another of the authoritarians he so reveres, Turkish president Recep Tayyip Erdogan, who urged the pull-out. He was probably pushing at an already open door, thanks to Putin.

In Helsinki Putin admitted for the first time that he had wanted Trump to win the presidential election. This was not prima facie evidence of a Manchurian Candidate situation. The worry is that with Trump nothing as sinister as brain washing is needed. The psychological impact on him of spending quality time with an admired “strong man” and a dose of flattery is probably enough.