The Washington Post’s Greg Miller reported Sunday that President Donald Trump’s confiscation of the translator’s notes from a one-on-one conversation with Russian President Vladimir Putin in 2017 was “unusual.” This is incorrect. It was unprecedented. There is nothing like it in the annals of presidential history.

It is also truly unusual that Trump failed to bring in a note taker, along with his translator, during his meetings with Putin, as almost every other president has done when meeting with foreign heads of state since the end of World War II. Usually the note taker is an official or aide with deep background in the subject under discussion.

Michael McFaul, who was President Barack Obama’s adviser on Russia, then his ambassador to Moscow, tells me that he routinely took notes in meetings between Obama and either Putin or his predecessor, Dmitry Medvedev. In some of these meetings, McFaul says, Obama took a few moments of “set-aside” time for a personal discussion with the Russian president; but in those instances, he briefed McFaul afterward, and McFaul then consulted with the translator to make sure that, in the notes of that debriefing, he got the wording as accurate as possible.

There are good reasons for presidents to bring a note taker with them to such meetings. First, they want a record of what was said, both to remind themselves later of what happened and to confirm or dispute some later account of the meeting, either by the foreign leader or some reporter. Second, the president’s national security officials want to know what was said so that they can orient policy accordingly. Third, historians value these notes, once they’re declassified, as a record of behind-the-scenes U.S. foreign policy.

In the Dwight D. Eisenhower Library, you can read the very detailed notes of the extensive conversations Ike had with Soviet Premier Nikita Khrushchev at Camp David in September 1959. It’s a fascinating glimpse of both men’s views of war, peace, and the international tensions of the day. It also reveals a ray of trust that might have brightened U.S.-Soviet relations, and transformed Cold War politics, had it not been snuffed out by the U-2 spy plane crisis one year later.

The John F. Kennedy Library contains a massive archive of exchanges—in the form of memorandums of conversation, telegrams, and transcripts of secret tape recordings—between JFK and the leaders of France, Great Britain, Germany, Russia, and many other countries. There are also, of course, the invaluable tapes of his lengthy discussions with his advisers during the 13 days of the Cuban missile crisis (which completely contradict the version of events put out, years earlier, by his “palace historians”).

Lyndon Johnson taped even more of his historically interesting conversations, and not just with world leaders.

Richard Nixon sometimes met with foreign leaders, including Soviet Premier Leonid Brezhnev, without a note taker. But according to historian Tim Naftali, a former director of the Nixon Presidential Library, he did tape-record those conversations—like Kennedy and Johnson, without the other party knowing it—and those tapes have been declassified.

Among the most fascinating documents of this sort are the notes—the ones taken by the American aide and the Soviet aide—of the 10 hours of conversations between Ronald Reagan and Mikhail Gorbachev at the historic 1986 summit in Reykjavik, Iceland. This was the summit where the two presidents, to the alarm of their aides, almost agreed to destroy all of their nuclear weapons, but for an irreconcilable dispute over the “Star Wars” missile defense system (Gorbachev wanted to ban testing of the system outside a laboratory, Reagan didn’t). The fascinating thing here is the fact that they had 10 hours of substantive conversation about arms control and nuclear strategy. Reagan, who is widely recalled as a bit of a dolt, was in fact well briefed on the subject; and while he had some wacky ideas, he fully understood the implications of those ideas. It is hard to imagine Trump holding court on such complexities for as long as 10 minutes.

Most recently, the National Archives released transcripts of the many hours of telephone conversations that Bill Clinton had with Boris Yeltsin on arms control issues in the early post–Cold War era.

The point here is that all of these presidents understood the value of keeping a record of conversations with foreign leaders—both for their own understanding of what was going on and for the enlightenment of posterity.

Trump cares nothing about either.

Whether his translator’s notes hold anything incriminating about Trump’s fealty to Putin, it is appalling that he would go into a one-on-one meeting with the Russian president without a note taker—especially given his shallow grasp of the issues and the very real possibility that he could have given away U.S. interests or disclosed vital secrets without understanding what he was doing. He also conducted his one-on-one with North Korean leader Kim Jong-un, at their summit in Singapore, without a note taker present.

Did Trump concede these issues in his one-on-one without telling his subordinates? We may never know.

In both cases, there were translators on both sides, but, as McFaul, a fluent Russian speaker, told me, their job is completely different from that of a note taker. The former has to focus on translating the foreign leader’s words to the president as quickly and accurately as possible. The latter has to transcribe what both sides are saying as fully as possible. It is very difficult to do both—impossible to do both well.

The irony—and perhaps the tragedy, for U.S. foreign policy and possibly (depending on what he did tell Putin) for Trump personally—is that the Russians, and probably the North Koreans, do have records of their one-on-one sessions with Trump. Putin did bring along a note taker. It is also likely that he or one of his aides tape-recorded the conversations. (The photograph of their tête-à-tête in Helsinki reveals a suspicious vase of flowers on the table between them.)

Quite aside from matters that may be of concern to special counsel Robert Mueller, who knows what concessions Trump may have made in these sessions? In the follow-on meetings that have since taken place between U.S. and North Korean negotiators, American diplomats have sometimes raised points that they consider vital—only to have their North Korean counterpart wave it away, saying, “Go talk with your president.” Did Trump concede these issues in his one-on-one without telling his subordinates? We may never know; some U.S. officials suspect he did.

Another appalling fact is that Republicans in Congress don’t want to know either. Rep. Adam Schiff, who is now the Democratic chairman of the House Intelligence Committee, tweeted on Sunday that, last year, he “sought to obtain the interpreter’s notes or testimony, from the private meeting between Trump and Putin. The Republicans on our committee voted us down.” Schiff asks, “Will they join us now? Shouldn’t we find out whether our president is really putting ‘America first?’ ”

The question is urgent not just for the historical record but for the political crisis that enmeshes us today, especially given the New York Times’ report on Friday that, in 2017, the FBI opened a counterintelligence investigation on whether Trump was working as, in effect, a Russian agent. Whatever the outcome of that probe, the fact that the question can be seriously raised—given the clear convergence, if not the outright collusion, of their interests—is worthy of several gulps.