Michèle Flournoy likes to say that during her years at Balliol College, Oxford, she “majored in rowing” and had the shoulders to prove it. Now under-secretary of defence for policy (and known as the brain of the Pentagon) she is using her brawn to muscle through a fundamental shift in US strategic doctrine. Her thinking is based on the concept of the “global commons,” which is in turn based on the old Royal Navy idea of promoting maritime supremacy while touting the freedom of the seas. Flournoy sees these global commons in a wider context that includes air and space and cyberspace as well as the oceans. Her essay in the latest issue of Proceedings, published by the US Naval Institute, is becoming required reading around the Pentagon.

She warns that “a series of recent events, including anti-satellite missile tests, piracy in the Gulf of Aden and off the east