Pelly, a country cannot impose martial law on another country, especially if they do not occupy it. Until N. Korea rolls into S. Korea, their declaration is void and meaningless. This is even more the case regarding their "martial law" on the U.S.
Don't get too distracted and woried by the mainstream media's new fixation with N. Korean rhetoric. Its purpose is to divert attention away from the Western Zionist imperialist's plans to attack Syria and Iran; and to hide other stories such as the LIBOR scandal. Also, the Jew owned and controlled media, which is an extension of the State Department and CIA, is just trying to get Iran to feel complacent and drop their guard; while concealing the atrocities against Christians in Syria, and other Syrian civilians loyal to Assad, committed by rebels supported by the U.S., NATO, Saudi Arabia and Israel.