All US Presidents from Reagan, to Bush 1, Clinton, Bush 2, Obama and Trump have failed to reverse the North Korean Nuclear program. Presidents from Eisenhower to Carter failed to prioritize and solve the North Korean rogue state issue.
China has long feared a refugee crisis flooding its borders if North Korea’s leadership collapses. South Korea does not want to pay the price of a second Korean war.
Sanctions have not worked because China has not enforced them on their end. China accounts for more than 90 percent of North Korea’s trade, it would be ideal for them to cut back that trade significantly. The problem is that Chinese officials have long feared that doing so would not only cause a collapse, but it would turn Pyongyang against them.
The USA would have to offer China a huge deal to entice China to not only give up North Korea but to prevent or make up for all of the big downsides.
The North Korean nuclear program has its roots in the 1950s and begins in earnest in 1989 with the end of the Cold War and the collapse of the Soviet Union, the main economic ally of North Korea. The Chronology mainly addresses the conflict between the United States and North Korea, while including the influences of the other members of the six-party talks: China, Russia, South Korea, and Japan.
The North Korean nuclear program can roughly be divided into four phases.
Phase I (1956–80) dealt primarily with training and gaining basic knowledge.
Phase II (1980–94) covers the growth and eventual suspension of North Korea’s domestic plutonium production program.
Phase III (1994–2002) covers the period of the “freeze” on North Korea’s plutonium program (though North Korea pursued uranium enrichment in secret) and
Phase IV (2002–present) covers the current period of a very active nuclear program
12 September: Clinton Former Secretary of State Madeline Albright admits North Korean “cheating” on the Agreed Framework occurred during the “Clinton Watch.”
28 September: North Korea says it has turned plutonium from 8,000 spent fuel rods into nuclear weapons.
26 June: A report by the Institute for Science and International Security estimates that current North Korea plutonium stockpiles is sufficient for four to thirteen nuclear weapons
4 July: North Korea test-fires at least six missiles, including a long-range Taepodong-2, despite repeated warnings from the international community.
9 October: North Korea announces that it has performed its first-ever nuclear weapon test. Measurements recorded only showed an explosion equivalent to 500 metric tons of TNT, as compared to the 1998 nuclear tests that India and Pakistan conducted which were 24–50 times more powerful. This could indicate that the test resulted in a fizzle. Some also speculated that the test may be a ruse using conventional explosives and nuclear material.
25 May: North Korea tests its second nuclear device
12 February: North Korea tests its third nuclear device.