In September 1991, President George H.W. Bush announced a series of sweeping measures fundamentally reshaping the American nuclear arsenal. One of them called for all U.S. ground-force tactical nuclear weapons to be returned from overseas bases and dismantled. Similarly, all tactical nuclear weapons on surface ships and attack submarines, as well as those associated with land-based naval aircraft, were to be withdrawn.
Eight days later, President Mikhail Gorbachev reciprocated, declaring that similar steps would be taken for Soviet nuclear forces.
As a result of these so-called Presidential Nuclear Initiatives, or P.N.I.'s, thousands of nuclear weapons on both sides were ultimately taken out of service and in some cases eliminated altogether — all based on unilateral, parallel actions, and all without an arms control treaty.