North Korea's Nuclear Weapons Program
North Korea announced its intention to reactivate its nuclear program in 10/2002, ejected I.A.E.A. inspectors in 12/2002, and proceeded to develop nuclear weapons. North Korea withdrew from the Treaty on the Non-Proliferation of Nuclear Weapons on 1/10/2003.
Pursuant to the Agreed Framework of 1994, North Korea agreed to abandon an earlier nuclear program in exchange for agricultural, energy, and economic aid. [Agreed Framework Between the United States of America and the Democratic People's Republic of Korea: signed 10/21/1994.] North Koreans were suffering from starvation due to a long-term famine, and North Korea alleged that the U.S. did not deliver all its promised aid.
North Korea also believed that the U.S. planned to attack it after attacking Iraq, because it was labeled part of the "Axis of Evil" by President George W. Bush on 1/29/2002. On 2/6/2003, North Korea threatened that an attack on North Korea would trigger "Total War" and a "Third World War." It also threatened a preemptive strike on U.S. troops in the demilitarized zone (DMZ). North Korea also said that it would view economic sanctions as an act of war.
North Korea requested direct dialogue with the U.S., but the U.S. refused to negotiate directly with North Korea until China agreed to host talks. (The U.S. has no formal relations with North Korea.) Talks occurred on 4/23-24/2003.
On 4/24/2003, North Korea announced that it had a nuclear weapon. On 5/12/2003, North Korea withdrew from an agreement with South Korea to keep the Korean peninsula nuclear-free.
Six-nation talks continued intermittently from 8/2003. On 10/9/2006, North Korea conducted its first underground nuclear test, increasing tensions. On 2/13/2007, in exchange for aid, North Korea agreed to shut down its nuclear facility and allow inspections by the I.A.E.A. Working groups were also established to work towards normalizing relations with South Korea, Japan, and the U.S.
On 12/11/2008, the six-party talks stalled because North Korea refused to agree on a plan to verify its declared nuclear capability.
In 1/2009, because of the hard line taken by South Korea's current conservative government (South Korea now refuses to provide food without cooperation on nuclear weapons and human rights issues), North Korea accused South Korea of preparing to wage war. On 1/30/2009, North Korea declared all peace accords with South Korea "dead", said their maritime boundary was nullified, and implied that it may initiate armed conflict with South Korea. (In 1999 and 2002, armed conflict broke out at this maritime border.)
In defiance of U.N. resolutions, North Korea successfully launched a missle test on 4/4/2009. South Korea, Japan, China, and the U.S. objected. North Korea then quit the six-party talks, calling them "useless". North Korea followed this with a second underground nuclear test on 5/25/2009. [See Wikipedia article on Six-Party Talks ]
Technically, the two countries remain at war. The armistice that ended the 1950-1953 Korean war was not signed by South Korea. It was signed by North Korea, China, and the U.N. The demilitarized zone and heavy fortifications on both sides divide the two. North Korea has one of the largest armies in the world. [See Wikipedia articles on the Korean War and the Korean Armistice Agreement.]