I'll be blunt.
You made a mistake with North Korea. The Japanese and South Koreans, your allies for decades now, are currently under threat from madmen who do "missile tests" whenever they so choose, and who kidnap their citizens for spying and experimentation purposes on occasion. These same madmen have nuclear weapon technology. Beyond such "small" concerns as alliances, your economy isn't exactly pure domestic - it is intricately tied to external economies, some of which are now at threat from this group of nuclear madmen.
*we* are you allies as well. And we live in a region that, like it or not, is a cornerstone of your economy as well - see "oil" in wikipedia. If you'd like to abandon *this* region to another group of madmen with missiles they'd like to top with nuclear warheads, by all means. We'll see how well that goes.
Also, a brief reminder - if North Korea or Iran ever launch a nuclear missile, the world as you know it may very well end. Mutually Assured Destruction isn't dead, and no one truly knows how any nuclear war will end today.
So, that's just *your* interests considered.