In May, Japan held its first-ever defense show, in Yokohama. The event coincided with an attempt by Prime Minister Shinzo Abe to modify Japanese laws so that Japan can participate fully in collective defense, meaning that the Japanese military can, for example, join U.S. forces under attack in Asian waters. Current law forbids such action. Thus U.S. naval forces can assist Japanese units in, say, protecting shipping en route to or from Japan—shipping on which Japan’s existence depends—but if those forces (and not the Japanese ones) come under attack, the Japanese cannot help. These laws are a legacy of the pacifist constitution imposed by the victorious United States after World War II. Japan has found a way to build defensive forces since the 1950s, but only on the grounds that the constitution cannot take away the inherent right of self-defense. The proposed changes can be traced in part to the rise of China and the relative decline of U.S. forces, particularly naval forces, in the Far East.
World Naval Developments - Collective Defense in the Pacific
By Norman Friedman