Striking developments in the relationship between America and Japan suggest that a new type of strategic alliance is brewing. In particular, a series of seemingly unrelated events point to important shifts that could have significant implications for both countries as they contemplate an era of sophisticated electronic warfare.

Fifty years after Japan and the US signed their treaty of mutual co-operation, Barney Frank, US congressman, in July described the stationing of US forces in Okinawa as a hangover from the second world war. Shortly after, John Roos, US ambassador to Japan, became the first American envoy to join the annual commemoration of the atomic bombing of Hiroshima. Then, Naoto Kan became the first Japanese prime minister in 25 years to instruct his cabinet to stay away from the annual event honouring Japan’s war dead, at the Yasukuni shrine.

Not only does all this suggest the strengthening of an old alliance, it also points to new possibilities for co-operation. Under their security treaty, the US and Japan agreed to help each other in the event of an attack on either side, although Japan’s pacifist constitution forbids it from having an active military. Yet military hardware, so essential for security 50 years ago, is no longer the only form of security threat that matters. Cyber security now requires equal attention.