During his 17-year rule, late North Korean leader Kim Jong Il poured scarce resources into Pyongyang's nuclear and missile programs to use as bargaining chips in negotiations with Washington, Seoul and Tokyo. At the same time, he sought to build unity at home by pitching North Korea's defiance as a matter of national pride as well as military defense.
North Korea has long cited the U.S. military presence on the Korean Peninsula, and what it considers a nuclear umbrella in the region, as the main reason behind its need for nuclear weapons. North Korea and the U.S. fought on opposite sides of the bitter, three-year Korean War. That conflict ended in a truce in 1953, and left the peninsula divided by heavily fortified buffer zone manned by the U.S.-led U.N. Command.
Sixty years after the armistice, North Korea has pushed hard for a peace treaty with the U.S. But when talks fail, as they have for nearly two decades, the North Koreans turn to speaking with their weapons.
With each missile and nuclear test, experts say North Korea is getting closer to building the arsenal it feels it needs to challenge Washington to change what it considers a "hostile" policy toward the longtime foe.
In 2008, after years of negotiations led by China, North Korea agreed to stop producing plutonium and blew up its main reactor northwest of the capital.
But in 2009, just months after Obama took office for his first term, Pyongyang fired long-range rocket carrying a satellite, earning U.N. condemnation and sanctions that North Korea accused Washington of initiating. In protest, Pyongyang conducted its second nuclear test and revealed it had a second way to make atomic bombs: by enriching uranium.
With nuclear negotiations stalled, North Korea forged ahead making missiles designed to reach U.S. shores and worked toward building a bomb small enough to mount on it — less with an actual attack in mind but to brandish as a warning to the wartime foe.