Chemical protective posture

Why does the mere threat of a chemical attack blunt an army that is never actually attacked?

An army equips itself thoroughly against chemical weapons: suits, masks, filters, detectors, decontamination units. The enemy has the capability but never uses it. Nothing arrives. And yet the army moves slower, communicates worse, and tires faster than it otherwise would.

If nothing happened, where did the loss come from? One familiar answer is deterrence — a weapon working by never being fired. But deterrence describes a threat that stops the other side acting. This runs the opposite way: a threat that leaves the other side free to act and taxes it the whole time it does.

Start with the timing, because everything follows from it. A mask put on after the agent arrives protects the next few minutes and does nothing about the breath already taken, and nerve agents act on a timescale that leaves no room for a considered response. So protection is only worth anything if it precedes the attack — the decision must be made before there is evidence one is coming.

Now ask what evidence a commander has. Detection helps, but notice what most of it does: it confirms an agent is present, which is to say it reports an exposure that has begun. That is very good to have and it is not a warning in the sense the decision requires. Add false alarms in both directions, and the fact that a suspicion of release — an odd shell burst, a report from a neighbouring unit — is often all there is.

So the choice is not "are we under attack" but "how much protection shall we wear against the possibility" — which is why real practice is a graded ladder rather than a switch: equipment carried, then the suit worn with the mask at hand, then everything sealed. From recollection, the American scheme names such levels explicitly; I will not recite the definitions, but the ladder is the general form.

What does sitting on that ladder cost? A suit keeps vapour out, and the same barrier keeps sweat's evaporation in, so the body's main cooling channel is throttled and work must be broken up with rest. A mask narrows the visual field, fogs, and muffles speech, so everything mediated by talking slows. Gloves remove fine motor control. Eating and drinking need an unmasking window. And the suit has a limited protective life once opened, so wearing it consumes it, turning time at posture into a supply problem. I will not quote figures for how far work rate falls or how quickly heat casualties appear: published values vary enormously with temperature, task and acclimatisation, and the argument does not need them.

Put the timing and the cost together and the mechanism appears. The cost accrues per unit of time spent at posture; time at posture is governed by uncertainty about whether an attack is coming; and that uncertainty is set by the adversary, who maintains it simply by holding the capability and staying unclear about his intentions.

Which gives an unpleasant corollary. If the tax is proportional to time at high posture, the cheapest way to impose it is not a large attack but an ambiguous or a small one — anything that forces a formation up the ladder and holds it there. The attacker pays almost nothing and buys degradation across a whole force. The asymmetry is complete on the other side too: the possessor knows when he does not intend to use the weapon, so he protects his own troops only in windows he chooses.

Is this testable? Clearly. If the cost is paid against uncertainty rather than attacks, degradation should track hours at posture and not the number of attacks; units with better detection and warning, and therefore less time sealed up, should lose measurably less; and a credible removal of the threat should restore performance quickly with nothing physical changing. The refuting observation would be degradation appearing only during and after actual releases, with better warning making no difference to posture time or output — which would mean the loss is a consequence of attacks after all.

Three things to hold steady.

First, this is a tradeoff of a particular kind. It is not like stealth, where a permanent design decision buys one property at the cost of others once and for all. Here the exchange is made repeatedly, in time, under uncertainty, and what is spent is the force's own effectiveness against an event that may never occur — which is why a lighter, cooler suit lowers the rate of the tax but not its structure.

Second, the correct response is not to stop protecting. The asymmetry between the errors is enormous: a low posture when an attack arrives is catastrophic, being needlessly sealed up merely expensive. A commander who over-protects is therefore behaving rationally, and the adversary is exploiting the rationality rather than a mistake. What reduces the tax is better warning — intelligence, detection at a distance, the discipline to come down the ladder promptly when sampling is clear — since all of those shorten time at posture without changing the odds of being caught.

Third, a caveat about the evidence. Because these weapons have been used comparatively rarely, much of what is claimed about degradation comes from exercises and trials rather than combat — and both the states that hold such weapons and the agencies that fund protection against them are interested parties in how large the effect is said to be.

• Why decontamination, rather than protection, is often the real limit on how long a force can operate in a contaminated area.
• How the same "posture held against a possibility" argument applies to air-defence alert states and blackout discipline.

Every term the collection defines is gathered in the glossary.