Why Do Officials Filch Classified Documents? One suspects they want a memento of their time in power. That doesn’t make the matter less serious.

It is a scandal that has intermittently consumed the attention of the press, and I think of a lot of regular people too, because they immediately apprehend the meaning of words like “unlawfully possessed top secret documents.” But people don’t quite know what to make of it. Everything gets so politicized so fast.

You don’t know what level of alarm to feel about the security breaches because you don’t know the documents’ exact contents. Are we talking about a scribbled note on an old Group of 20 schedule, or are we talking about nuclear codes? Is it an amusingly phrased section from an old intelligence report saying the Danish foreign secretary’s husband is said to be romantically involved with a hairdresser whose social-media posts suggest neo-Nazi ties? Or is there a paper in there revealing the names of U.S. intelligence assets in Iran?

TOP SECRET and ConfidentialBecause you don’t know the content, you can’t infer the motive. Why might a government official illegally bring home and keep classified documents? What did he intend to do with them? “I thought I’d need it for my memoirs.” “I must admit I thought it an unimportant document to anyone but me—it was inappropriately classified because the default mode of clerks is to say, ‘Classify it.’ So I harmlessly declassified.” Or, “Heck, there was no motive because there was no crime! In the last day at the White House my aides scooped the papers off the top of my desk, saw no markings, plopped them in a box with other papers, sent the box to my house where they put them in my basement, and we never knew there were any secret papers in there because we never opened the box!”

There could be other motives. Here’s one that’s too sweet, but early on it’s where my mind went. I thought of the psychology of it.

This may not sound true but I’ve seen it. People who were once in power—people who ran the world and then retired, or stepped down to do something else—as time passes and the years go on they can’t believe it happened to them. They can’t believe they had the pope on hold. They gesture to the silver framed picture on the table in the bedroom: “That’s us and the shah.” When they were running the world they took it in stride, but afterward they’re sort of concussed. And maybe they take something sensitive as a memento, as a souvenir of their greatness. I think they know they’re going to want to prove to others, and themselves, that it really happened. “See? We went to Robben Island for a ceremony with Mandela.” Because as years pass you can never believe you were at the center of everything. And you kind of want to show yourself you were.

That probably doesn’t have anything to do with all the secret-document stories. Which probably in their essence have more to do with entitlement and arrogance. The rules are for little people. Also laziness. A former White House official noted to me, “People bring things home to read because they don’t want to stay at the office any more that day. They think, ‘No one will see it,’ ‘It’s in my custody.’ Wrong, and illegal.”

In the case of Donald Trump, we still don’t know exactly what the government seized at Mar-a-Lago. He knew documents were there and refused requests to turn them over. The Federal Bureau of Investigation removed a reported 33 boxes of papers, including those whose classification ranged from confidential to top secret.

In Joe Biden’s case, documents were found in November at the Penn Biden Center in Washington. Others were later found in his home in Wilmington, Del., some famously stored in the garage near his Corvette. Another few documents were found in Wilmington in mid-January, and more after that. CNN has reported, citing anonymous sources, that included were “10 classified documents including US intelligence memos and briefing materials that covered topics including Ukraine, Iran and the United Kingdom.” Some files bore the classification used for highly sensitive information obtained from intelligence sources.

Some of the Biden documents hail back to his days in the U.S. Senate, which makes him look like a serial absconder. The White House has said the material was inadvertently misplaced. Mr. Biden himself said on Jan. 10 that he was “surprised to learn” that there were any documents at the Penn office and doesn’t know their contents. It’s been noted he didn’t say anything about the documents in Wilmington. And the White House didn’t disclose the discovery of the original documents in November, or even when more were found in December. Mr. Biden also said “I think the American people know” he’d be serious about the handling of documents, and it struck me as soon as he said it: I don’t think they know that.

Here is a hypothesis from a sophisticated acquaintance with broad governmental experience: Joe Biden is “deeply sensitive about his reputation,” and having been proven wrong on various stands he’s taken in the past, he just might have decided to have documentation around him that showed his thinking was based on advice and insight from various government agencies, such as the intelligence community. Why not have nearby some documentation that might be used to buttress his past position? And that you might show around a bit, as needed and off the record.

That is conjecture. But the nature of these cases makes you want to guess what was really going on.

Special counsels have been appointed in the cases of Messrs. Trump and Biden. In the Mike Pence case, one doesn’t imagine another will be, because his assertion that the documents were taken inadvertently seems believable.

It’s funny how Mr. Trump figures in here, because he enjoys a special benefit. No one really ponders his motives because he’s . . . Donald Trump. There have been reports in the past that he sometimes took secret documents, tore them up and flushed them down the toilet. It was easy to assume after the FBI conducted its raid that Mr. Trump just wanted, in his screwball way, to show members of the Mar-a-Lago Club Kim Jong Un’s handwriting. He wanted to show them how much Mr. Kim loved him because everyone loved him and the world worked when he was in charge.

In any case it’s bad to be showing the world that U.S. leaders can be so derelict in their handling of top secret information. It makes the processes of our government look unprofessional, chaotic, ad hoc.

Congress is right to want to know exactly what’s in all those documents, what danger their cavalier handling posed, and how they wound up where they wound up. They should also look at the classification process itself. Do we overclassify or underclassify things?

As scandals go this is a worthy one—it’s not blown up nonsense over nothing. It won’t likely go away soon and may have serious political implications. It’s not bad to be showing the selfish, abusive or slovenly that if they break the laws on classified documents they will pay a price.