Deterrence Without a Doctrine

Deterrence is a claim about someone else's reasoning. It asserts that an adversary, contemplating an action, will decline because the expected cost exceeds the expected gain. Everything else in the field is an attempt to make that claim credible.

Credibility requires three things that are difficult to hold together: capability the adversary believes is real, willingness the adversary believes will be exercised, and communication clear enough that the adversary understands what triggers the response. Current policy across most of the Western alliance is strong on the first and increasingly unclear on the other two.

Capability has outrun explanation

Procurement has accelerated. New systems, expanded munitions stocks, forward deployments, and a serious effort to rebuild industrial capacity that had been allowed to atrophy. These are real changes and they were overdue.

What has not kept pace is declaratory policy, the public statement of what the capabilities are for. In its absence, adversaries infer intent from deployment patterns, and allies infer commitment from the same evidence. Both inferences can be wrong, and the errors run in opposite directions: an adversary can conclude that a red line is soft when it is not, an ally can conclude that a guarantee is firm when it has never been tested.

Ambiguity is a policy choice, and it has to be chosen deliberately rather than arrived at by default.

The problem of the middle rung

The hardest gap is in the middle of the escalation range. At the top end, the doctrine is old, well developed, and understood by everyone. At the bottom end, sub threshold activity is annoying but survivable and everyone is doing it.

The middle is where the current disagreements live. A serious cyber intrusion into critical infrastructure. Interference with subsea cables. Seizure of a small feature by forces without insignia. Sustained interference with navigation in a contested waterway. These are precisely the actions an adversary would choose if it wanted to test a commitment while remaining below the level that would trigger the responses everyone has planned for.

Responses to that middle range are largely improvised. Deciding what to do while it is happening, under time pressure, with incomplete information, is the worst available way to make the decision, and it is the method currently in use.

Allies need to know the answer too

Deterrence is not only aimed at adversaries. Allies are also making decisions based on their reading of a guarantee: how much to spend, whether to develop independent capabilities, how far to accommodate a neighbor they would rather not accommodate.

An ally uncertain about a commitment hedges, and hedging by allies reduces the credibility of the commitment further. The loop is self reinforcing in the wrong direction, and it can run a long way before anyone tests it directly.

Writing it down

The unglamorous recommendation is a published doctrine that states, with enough specificity to be useful, what categories of action trigger what categories of response.

Every professional objection to this is legitimate. Specificity creates a floor an adversary can operate beneath. Public commitments constrain future decisions. Allies will demand clarifications that are politically difficult to give.

The alternative, however, is what exists now, which is a set of expensive capabilities attached to an unstated theory that the people who would have to act on it have never had to articulate. Systems do not deter. Beliefs about what will happen deter, and beliefs require statements.

Doctrine is a public document by design, and that is the part most often forgotten in arguments about it. Its function is to tell an adversary what will happen, which requires that the adversary can read it.

A posture that is never stated cannot perform that function. It can deter through capability alone, which works less reliably and requires the other side to guess correctly about intent.

The budget documents are where an unstated posture becomes legible anyway, because procurement reveals priorities more honestly than any statement of policy.

That is a poor substitute for saying so. A programme can be read several ways, and an adversary reading it wrongly is exactly the failure deterrence exists to prevent.

The classification system explains part of the silence and cannot justify all of it. Capabilities are properly secret. The conditions under which a state would use them are the thing that has to be public to work.

The authorities that raise the force and the emergency powers that would be invoked are both public, which produces an odd asymmetry: the legal machinery is visible and the threshold for using it is not.

The practical consequence is that allies plan against an inference. A partner deciding what to build, and what to rely on, is reading procurement and reading silence, and the second is not something anyone can plan against.

Which is the actual gap. Not an absence of capability, which is substantial, but an absence of the stated conditions that would let anyone, friendly or otherwise, know what it is for.