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.