Much of the time, it’s simply because people are just not very good at keeping secrets.

Over the weekend, I picked up a political classic that I had somehow never sat down to actually study in any detail: Carl Bernstein and Bob Woodward’s All the President’s Men. For anyone who hasn’t read it, it’s a brisk and engaging read. And it’s easy enough to see why it sold a gazillion copies when it was published in June 1974 as the Watergate scandal headed toward its frenzied conclusion.

(I’m aware that Woodward/Bernstein don’t exactly go out of their way to keep themselves from being the center of attention, with a heroic presentation, in their book and that their journalistic conclusions about Watergate have come under fire over the years and are the subject of serious and sober revisionist histories, including in Jim Hougan’s Secret Agenda, James Rosen’s The Strong Man, and Geoff Shepard’s The Nixon Conspiracy. And, of course, the Robert Redford/Dustin Hoffman movie version turns all this up to eleven, as one would expect of a Hollywood production.)

But whatever one might think of “Deep Throat” — there are credible, or at the very least, intriguing hypotheses that Woodward and Bernstein’s famous source Deep Throat, a.k.a. former FBI official Mark Felt, was an unreliable witness at best and, at worst, a composite, semi-historical agglomeration of several separate sources — one of the most interesting aspects of this celebrated, early-Seventies account of shoe-leather reporting is that the best way to elicit information from those in the know was to simply call them up and ask.

Amazingly, despite being in the thick of a serious national political scandal, many people — important officials, or not, famous, infamous, or not, implicated in the crime or cover-up, or not — would simply spill the tea when a reporter showed up at their doorstep or placed a call to their home or office and asked just what they knew.

Some of this is probably an artifact of an age in which people habitually answered their phones when they rang and of an era in which our institutions and their representatives — such as, say, the Washington Post and a couple of its reporters — automatically evoked more trust than they would today.

But I think the main point is that most people, when they know a bit of privileged information, are not very good at keeping mum, even when saying anything at all could hurt their organizations, their cause, their employers, even themselves.

Woodward and Bernstein are able to — simply by asking — get tongues wagging: Campaign financiers describe their group’s money-laundering operations, local district attorneys open safes and share confidential bank and phone records attained via subpoena, secretaries describe witnessing document-shredding operations, White House officials try their best to formulate innocent explanations for how and why money changed hands, Department of Justice employees confirm elements of secret testimony delivered to grand juries, cops share evidence taken off arrested individuals’ persons, employers describe the personal histories and potential whereabouts of former employees.

In one amazing incident described early in the book, in the days after the initial June 17, 1972, arrests at the Watergate Complex, Bob Woodward simply calls up E. Howard Hunt at his office — Hunt was a former CIA officer and one of the burglars’ primary links to the White House and the Nixon reelection campaign — and asks Hunt why his name and phone number were listed in the address books of two of the burglars caught breaking into the Democratic National Committee.

“Good God!” Hunt exclaims, per Woodward’s report. He then added quickly before hanging up: “In view that the matter is under adjudication, I have no comment.”

It’s easy to see why Woodward and Bernstein thought the “Good God!” exclamation was more indicative of Hunt’s involvement in the whole thing than his “no comment.”

Why do leaks happen? Well, sometimes it’s because someone has an ax to grind, or out of ideological or political motivations, or in the hope of personal advancement. But much of the time, it’s simply because people are just not very good at keeping secrets.