For years the United States has been working closely with Japan on developing and improving missile defense systems to shoot down missiles that are launched from North Korea. The Japanese are in perilous situation no matter what because any ICBM launched by North Korea will most likely fly over Japanese soil. In July 2006 North Korea test fired a TD2 along with six other short range missiles. The TD2 failed shortly after launch. The problem this creates for Japan is falling debris or, worst case, entire rockets parts or the war head impacting Japanese territoy causing serious damage.
While the Japanses have deployed their anti-missile destroyers to intercept missile debris if need be, the Obama administration once again sits impotent as a dictator stares down international opposition. While North Korea has said that any attempt to intercept the missile will be considered an act of war, apparently lauching an ICBM over the sovereign territory of another nation is not.
The Obama administration has significantly backed off the concept of missile defense by back peddling on the European sites under pressure from Russia and now standing down and letting North Korea launch their newest ICBM. I would suggest the current administration take another look at this issue based on the proflieration of both nuclear and missile technology happening in our world today.