A process in which two or more states, feeling themselves to be insecure or threatened, acquire armaments, each side responding to the acquisition of arms by the other with a further build‐up of its own. This action–reaction mechanism may acquire a momentum of its own, fuelling perceptions of insecurity, threat, and the need for more armaments. This is particularly so during times of rapid technological innovation, as in the “naval race” between Britain and Germany to build Dreadnoughts before World War I. A more recent example was the US–Soviet arms race, especially their competition for strategic nuclear weaponry, which started after World War II (see cold war). Some believe arms races to be a cause of conflict; to others they are a reflection of underlying political distrust, not a cause of it. One theory on arms races is that, if controlled at a key stability point, they may contribute to some kind of strategic stability, akin to a balance of power.