The most instructive thing to happen this fortnight was an irony: that the war waged to weaken Iran has, through the world's energy markets, materially strengthened Russia, funding the Kremlin's war in Ukraine with the oil-price shock of the Gulf. But the irony is worth treating not as an irony but as an instance of a law, the law of unintended consequences, because in a world as densely interconnected as ours it has stopped being the occasional surprise that punctuates strategy and become the central fact that strategy must reckon with, and mostly does not.
The sociologist Robert Merton gave the phenomenon its rigorous treatment nearly a century ago, in an analysis of what he called the unanticipated consequences of purposive social action. Merton's insight was that deliberate action aimed at a goal reliably produces effects beyond the goal, and that these unanticipated effects arise not from stupidity or carelessness but from structural features of action itself: from the impossibility of foreseeing all the consequences of an act in a complex system, from the way the immediate interest in the intended result crowds out attention to the secondary ones, and from the sheer interconnection of a world in which every action propagates through channels the actor did not model and often did not know existed. The strategist plans for the intended consequence, the destruction of Iran's programme, and does not plan for the second-order effect, the oil-price shock, or the third-order effect, the Russian revenue windfall, or the fourth, the funding of a European war, because these lie outside the frame of the intention, in the vast space of everything the action also does that it was not for.
The counterargument, and it is a fair one, is that this can become an excuse for paralysis or for cynicism, the claim that since every action has unforeseeable consequences, no action can be judged and no strategy attempted, which is both false and dangerous, because inaction has unintended consequences too, and the demand for perfect foresight before acting is a recipe for never acting at all. This is true, and I do not draw the fatalist's conclusion. The point is not that unintended consequences make strategy impossible; it is that they make a particular kind of strategy, the kind that plans only for its intended result and treats the rest of the system as inert background, reliably catastrophic, and that this narrow kind is precisely the kind that great powers, intoxicated by the clarity of their immediate objective, most often practise. The failure is not acting despite uncertainty; it is acting as though the only consequence that mattered was the one you intended, in a system that guarantees there will be others, often larger, often reversing the very advantage you sought.
Because that is what makes this fortnight's irony more than an irony. The Gulf war's planners had a clear and measurable intended consequence and pursued it with tactical brilliance, and the world's interconnection then delivered a set of unintended ones that may well outweigh it: an enriched Russia, a funded war in Ukraine, a global economic shock, a hardened Iran, a proliferation lesson taught to every watching state. None of these was the goal; all of them were the predictable output of a purposive action in a system too complex for the actor's frame, and the tragedy is that they were predictable in the general even though not in the specific, because the law of unintended consequences does not tell you which blow will land elsewhere but it tells you, with certainty, that blows will. A strategy worthy of the name would treat that certainty as its central design constraint, would ask not only what its action is intended to achieve but what else, in a connected world, it will inevitably set in motion, and would weigh the intended good against the unintended harm that the interconnection guarantees. The Gulf war's strategy did not. It planned for the target and got the world, and the world, this fortnight, sent the bill to Kyiv.