The proposition that Europe can accelerate rearmament by redirecting underused civilian factories towards defence is attractive because it appears to supply time, equipment and skilled labour without waiting for new industrial capacity to be built. It becomes considerably harder once it is lowered from the level of sectors to the level at which defence output is actually created. A plant may have floor space without suitable equipment. A machine may be technically adaptable without being available when required. An automotive production engineer may be able to redesign a product for serial manufacture without owning the design data needed to alter it. A qualified military product may cease to be qualified when its manufacture moves to a new process. A government may fund a programme without reserving production capacity. A factory may assemble units without those units having been accepted by the customer. And a line may run for a year on the strength of an authorisation that does not cover what it is making. Each of those gaps is a separate failure mode, and each has to be closed before anything can be counted as readiness. The question that matters for European rearmament is therefore not how much apparently spare civilian industrial capacity exists, but under what technical, contractual, financial and legal conditions particular civilian resources become additional, qualified and reliably available defence output without destroying the civilian activity on which those resources depend. Five cases in France, Germany and the Netherlands now allow that question to be answered with something better than inference, because in one of them the whole chain has been completed and in the others it has not.