Ukraine, the holder of the third largest stockpile of nuclear weapons, agreed to give them up in signing the Budapest Memorandum of 1994. In return for de-nuclearizing, the United States, the United Kingdom, and Russia assured Ukraine’s territorial integrity. When Russia annexed Crimea contrary to international law and Russia backed an invasion of Eastern Ukraine, neither the United States nor the United Kingdom fulfilled its obligations under the Budapest Memorandum to protect Ukraine’s territorial integrity. In its hostile actions against Ukraine, Russia broke the foundation of postwar peace; namely, the sanctity of existing national boundaries.
I find it strange that, in the discussion of the de-nuclearization of North Korea, reference is made mainly to Libya’s Gadhafi giving up his nuclear program, as an example of the untrustworthiness of major-power guarantees. Gadhafi voluntarily allowed in inspectors who oversaw the dismantling of the Libyan weapons program, but he received no guarantees of personal safety or territorial integrity from the major powers.
The Ukraine case, on the other hand, constituted a clear abrogation of treaty obligations on the part of the United States and the United Kingdom, and, of course, Russia. If General Secretary Kim of North Korea has doubts about entering an agreement with the United States that would leave him without nuclear weapons, he should ponder the case of Ukraine.
A nuclear Ukraine would likely still be in possession of Crimea and not have Russian troops and equipment in its East.