When the soviet union broke up in 1991 Ukraine possessed the worlds 3rd largest nuclear arsenal...1,900 warheads
the Budapest Memorandum
When the USSR broke up in late 1991, there were nuclear weapons scattered in the resulting post-Soviet states. The George H. W. Bush administration attached highest priority to ensuring this would not lead to an increase in the number of nuclear weapons states. Moreover, as it watched Yugoslavia break apart violently, the Bush administration worried that the Soviet collapse might also turn violent, raising the prospect of conflict among nuclear-armed states. Ensuring no increase in the number of nuclear weapons states meant that, in practice, only Russia would retain nuclear arms. The Clinton administration pursued the same goal. With the prospect of extending the Non-Proliferation Treaty indefinitely looming, an alternative course that allowed other post-Soviet states to keep nuclear weapons would have set a bad precedent.
Before agreeing to give up this nuclear arsenal, Kyiv sought three assurances. First, it wanted compensation for the value of the highly-enriched uranium in the nuclear warheads, which could be blended down for use as fuel for nuclear reactors. Russia agreed to provide that.
Second, eliminating ICBMs, ICBM silos, and bombers did not come cheaply. With its economy rapidly contracting, the Ukrainian government could not afford the costs. The United States agreed to cover those costs with Nunn-Lugar Cooperative Threat Reduction assistance.
Third, Ukraine wanted guarantees or assurances of its security once it got rid of the nuclear arms. The Budapest Memorandum provided security assurances.
America said it would act if Russia violated the Budapest Memorandum. That was part of the price it paid in return for a drastic reduction in the nuclear threat to America. The United States should keep its word and continue to arm Ukraine.
The furor over President Donald Trump’s sordid bid to extort the president of Ukraine into investigating his potential 2020 political opponent raises an obvious question: Why should the United States care so much about Ukraine, a country 5,000 miles away?
www.brookings.edu