North Korea breaks non-nuke program treaty. North Korea admits to nuclear weapons for the reason of self-defense.
North Korea continues testing missiles, including testing their first nuclear missile underground. They also conduct another test in 2009.
North Korea sinks South Korean warship. The North claims to have missiles that can hit the US. North Korea launches own satellite into orbit and continues to do nuclear test at an attempt to reach the goal of having a nuclear war head hit the mainland of the US. Tension continues to rise over the US and North Korea with neither one giving up.
2010 - Present
2006-2009
2003-2005
We can say that North Korea and the US have been in high tension ever since the US helped South Korea in the Korean War. North Korea continues to make silly threat against the US. While the US and the United Nations tries to stop North Korea from making weapons of mass destruction.