Note that Russia along with the US, France, UK signed a Treaty guaranteeing Ukraine's borders in exchange for them destroying their nukes.
Nuclear weapons and Ukraine - Wikipedia, the free encyclopedia
Already on July 16, 1990 the Verkhovna Rada adopted the Declaration of State Sovereignty of Ukraine where it announced that Ukraine will hold to the three non-nuclear principles: not to use, not to produce, and not to stockpile nuclear weapons. In November 1993, the Ukrainian parliament adopted a resolution On the Ratification of the Treaty Between the USSR and USA On the Reduction and Limitation of Strategic Offensive Weapons of June 7, 1991 and the Lisbon Protocol to the Treaty of May 23, 1992. In his speech in parliament the Prime Minister of Ukraine Leonid Kuchma however advocated to preserve in Ukraine the most effective and powerful part of the Ukrainian nuclear arsenal—46 ICBM SS-24 which could have been kept for a long time.
The next stage was the signing on January 14, 1994 of the Trilateral Statement by the Presidents of Ukraine, Russia, and the United States under which Ukraine was to destroy all nuclear weapons on its territory, including strategic offensive weapons. Ukraine, Washington and Moscow reached an agreement in January that allowed for the dismantling of Ukraine's 176 Intercontinental ballistic missile (ICBMs) ahead of Kiev's formal ratification of the Nuclear Non-Proliferation Treaty (NPT).[3][4] France and China provided unilateral security assurances in the form of diplomatic notes. The missiles—130 SS-18s and 46 SS-24s—carried about 1,800 nuclear warheads altogether.
Before voting on accession, Ukraine demanded from Russia, the USA, France and the United Kingdom a written statement that these powers undertook to extend the security guarantees to Ukraine. Instead security assurances to Ukraine (Ukraine published the documents as guarantees given to Ukraine[5]) were given on 5 December 1994 at a formal ceremony in Budapest (known as the Budapest Memorandum on Security Assurances[6]), may be summarized as follows: Russia, the UK and the USA undertake to respect Ukraine's borders in accordance with the principles of the 1975 CSCE Final Act, to abstain from the use or threat of force against Ukraine, to support Ukraine where an attempt is made to place pressure on it by economic coercion, and to bring any incident of aggression by a nuclear power before the UN Security Council.
