Explained | When and how did Ukraine give up its nuclear arsenal?

Ukraine was the country with the third-largest stockpile of nuclear weapons when the Soviet Union collapsed

The story so far: Russia has launched a large-scale military operation against Ukraine. The act was described as a “full-scale invasion of Ukraine” by the country’s Foreign Minister Dmytro Kuleba. Loud blasts were heard from the Ukrainian cities of Kyiv, Kharkiv, and Odesa.

As Ukraine battles powerful Russian armed forces, leaders of the country have expressed regrets about giving up their nuclear weapons which they believe might have held off an invasion of their territory by Russian President Vladimir Putin.

At the time of its independence from the erstwhile Soviet Union in 1991, Ukraine had the third-largest stockpile of nuclear weapons in the world. Things, however, changed when the country became a signatory to the Nuclear Non-Proliferation Treaty (NPT) in 1994 alongside Belarus and Kazakhstan, the other two countries that were left with nuclear weapons after the collapse of the Soviet Union.

At the time of U.S.S.R. dissolution, Ukraine had an estimated 1,900 strategic warheads, 176 intercontinental ballistic missiles (ICBM), and 44 strategic bombers, according to the Arms Control Association of the U.S.

The Strategic Arms Reduction Treaty (Start) was a bilateral treaty signed by former U.S. President George H.W. Bush and Soviet President Mikhail Gorbachev in 1991. It limited the number of ICBMs and nuclear warheads that the countries could possess. The treaty went through a period of turmoil when the Soviet Union ceased to exist, casting aspersions on its legitimacy. Ukraine, Kazakhstan, and Belarus signed a protocol in Lisbon in 1992 making them “successor states” of the Soviet Union.

The treaty obligated the successor states to join the Nuclear NPT at the earliest and the nuclear weapons were to remain under the control of a “single unified authority” until then.

Following the Lisbon protocol, differences between Russia and Ukraine on the latter’s status as a nuclear state came to the fore, raising concerns related to nuclear disarmament.