Taking a wild-ass guess (because that’s the best I can do), I imagine any Intelligence Service is going to bat below the Mendoza Line, because the Enemy gets a vote, too — when his best and brightest are doing their best to fool your guys, it’s certain your guys are going to get fooled a lot.

There’s also another version of the Historian’s Fallacy in play with Intelligence work:

The historian’s fallacy is an informal fallacy that occurs when one assumes that decision makers of the past viewed events from the same perspective and having the same information as those subsequently analyzing the decision. It is not to be confused with presentism, a similar but distinct mode of historical analysis in which present-day ideas (such as moral standards) are projected into the past. The idea was first articulated by British literary critic Matthew Arnold in 1880 and later named and defined by American historian David Hackett Fischer in 1970.

Things that seem obvious in retrospect weren’t at the time. That’s the “formal” Historian’s Fallacy, if you like. But there’s another one, that we could call the “Narrative Fallacy” or the “Assumed Rationality Fallacy” or something (I stink at titles). Historians are, or at least should be, acutely sensitive to the danger of seeing patterns that aren’t really there (in a very real sense, “conspiracy theorists” e.g. McGowan are just Historians manqué. Coincidences are coincidental, and without training and practice and — crucially — an experienced hand to smack you upside the head for going farther than the available sources allow, it’s easy to run wild with them. So-and-So knew Joe Blow … yes, but that does not automatically mean that So-and-So conspired with Joe Blow).

Compounding it further: It’s indeed rational to assume rationality on your enemies’ part, so some catastrophic intelligence “failures” have come because analysts were unwilling to acknowledge that the enemy was, in fact, making a mistake. It’s a bit pricey, but I highly recommend James Wirtz’s The Tet Offensive: Intelligence Failure in War (here’s a preview page of a review at JSTOR, which points to a trade journal, American Intelligence Journal. Wirtz is a professor at the Naval Postgraduate School; I bet his book rattled a lot of cages that needed rattling). Breaking it out a bit further, and these categories are mine, not Wirtz’s:

In the case of Tet, there was top-level structural “failure” that hardly deserves the term “failure” — the NVA’s intelligence boys were no fools; they were bright guys doing their damnedest to put one over on the American intelligence crew, and they had some success at it. That’s only “failure” in the sense that in binary system, a win for them is a loss for you — you “failed” to win the game against a highly skilled, highly motivated opponent. The Americans didn’t fail to recognize that The Enemy Gets a Vote; they just didn’t realize how he’d voted.

But there was what I’ll call “Narrative” failure, and that’s all on the Americans. They seem to have decided that the North Vietnamese were not only losing the war, but knew themselves to be losing the war. So what the North Vietnamese saw as merely “the next phase of the plan”, the Americans saw as “increasing desperation”. Which led to other Narrative Failures. I might be misremembering the details, so check me on this, but I believe that the Americans were correct despite themselves about the attack on the big Marine base at Khe Sanh — it was indeed a diversion. But the Americans somehow concluded that it was a diversionary attack, specifically a “spoiling attack”, on something the NVA shouldn’t have known about in the first place — a top secret operation called “Muscle Shoals” (in Wiki under Operation Igloo White).

In reality, the Khe Sanh attack was a diversion against the main Tet operation, and it worked so well that it took a week or more, IIRC, for Westmoreland to come around. He insisted on interpreting the Tet “uprising” as yet a further diversion — a diversion in support of what he assumed was the main NVA operation, the attack on Khe Sanh!

Those are Narrative Failures. Twitter didn’t exist then, but we could nowadays profitably call them “Twitter Failures”. Whatcha gonna believe, your own lying eyes or the blue checkmarks in the Pocket Moloch?

All of which was aided and abetted by the third kind of failure, that “Assumed Rationality” failure. One CIA analyst, Joseph Hovey, not only predicted the Tet Offensive, but got large parts of it exactly right. But Hovey had a hard time believing his own analysis, because its central assumption was that the North Vietnamese were, in fact, making a mistake. The North Vietnamese did not, in fact, have the forces in place to do what they wanted to do. They were suffering a catastrophic Narrative Failure of their own, one endemic (it seems reasonable to say) to Communist regimes — since political officers are highly encouraged to submit exaggerated reports of unit strength and morale (and often lethally discouraged from reporting the opposite), the NVA thought they had far more, and far better prepared, forces than they actually did.

In an Alanis-level irony, US military intelligence had a better idea of the NVA’s strength than the boys in Hanoi did. (They confirmed this, in fact, when they nabbed a high-level NVA defector, who only “rallied” because the formation he was sent south to lead didn’t actually exist!). When faced with the possible conclusion that the Enemy is about to make a big mistake, it’s only rational to assume that something else is going on. Hovey knew that, of course, and that’s one of the main reasons his analysis went nowhere — being a conscientious professional, he noted at the outset that his analysis was premised on the NVA setting up to make a big mistake, which seemed extremely unlikely.

Given all that, if I had to guess, I’d bet that the KGB had a similar record, if the truth is ever known, because they had similar problems. They had a different, more systematic kind of Narrative Failure, I’d imagine — “Marxism-Leninism” vs. “bow-tied Ivy Leaguers running around cosplaying Lawrence of Indochina” — but it probably all washed out in the end. It’d be extremely interesting to hear about the Vietnam War from the KGB’s side …

Severian, “Friday Mailbag”, Founding Questions, 2023-04-15.