With his domestic support on the decline, Japanese Prime Minister Shinzo Abe has reached the end of his diplomatic tether and should admit that playing the "China threat" card has not helped to win him the public's approval.

July opinion polls in Japan show the lowest approval ratings for the Abe Cabinet since it came into office in December 2012.

The reason is evident: After 20 months of busy "global diplomacy" visiting 47 countries or territories, Abe has been forced into a corner by his souring of relations with two of Japan's most important neighbors, China and South Korea.