I think North Korea is more of a threat to South Korea (ROK), than to Japan. Japan occupied the Koreas in the early 20th century.
I think China might be pulling the strings in some nefarious manner with how North Korea blusters and acts.
I think Taiwan is at risk if the Gulf War II is launched.
You might be on to something. The Red Chinese could be using NK as a proxie to test W's resolve in regard to other plans they have. If things get too hot, they can phone Kim and he will heel to his Chinese paymasters.
I seriously look at Bush doing a "twofer,' or something very close to it.