By Joseph S. Nye Jr*
Russia’s invasion of Ukraine has revived many questions about nuclear deterrence. Whatever the outcome of what could be a long war, the issues it has raised won’t go away.
In 1994, Ukraine surrendered the nuclear weapons it had inherited from the Soviet Union in return for security guarantees from the United States, the United Kingdom and Russia. But those guarantees turned out to be worthless, and because Ukraine isn’t a member of NATO, it’s not covered by the extended deterrence of the US nuclear umbrella.
