Mutual assured destruction in the context of "Dassault Mirage IV"

The Strategic Defense Initiative (SDI), derisively nicknamed the Star Wars program, was a proposed missile defense system intended to protect the United States from attack by ballistic nuclear missiles. The program was announced in 1983 by President Ronald Reagan, a vocal critic of the doctrine of mutual assured destruction (MAD), which he described as a "suicide pact". Reagan called for a system that would end MAD and render nuclear weapons obsolete. Elements of the program reemerged in 2019 under the Space Development Agency (SDA).

The Strategic Defense Initiative Organization (SDIO) was set up in 1984 within the US Department of Defense to oversee development. Advanced weapon concepts, including lasers, particle-beam weapons, and ground and space-based missile systems were studied, along with sensor, command and control, and computer systems needed to control a system consisting of hundreds of combat centers and satellites spanning the globe. The US held a significant advantage in advanced missile defense systems through decades of extensive research and testing. Several concepts, technologies and insights obtained were transferred to subsequent programs. Under SDIO's Innovative Sciences and Technology Office, investment was made in basic research at national laboratories, universities, and in industry. These programs have continued to be key sources of funding for research scientists in particle physics, supercomputing/computation, advanced materials, and other critical science and engineering disciplines.

The Atomic Age, also known as the Atomic Era, is the period of history following the detonation of the first nuclear weapon, The Gadget at the Trinity test in New Mexico on 16 July 1945 during World War II. Although nuclear chain reactions had been hypothesized in 1933 and the first artificial self-sustaining nuclear chain reaction (Chicago Pile-1) had taken place in December 1942, the Trinity test and the ensuing bombings of Hiroshima and Nagasaki that ended World War II represented the first large-scale use of nuclear technology and ushered in profound changes in sociopolitical thinking and the course of technological development.

While atomic power was promoted for a time as the epitome of progress and modernity, entering into the nuclear power era also entailed frightful implications of nuclear warfare, the Cold War, mutual assured destruction, nuclear proliferation, the risk of nuclear disaster (potentially as extreme as anthropogenic global nuclear winter), as well as beneficial civilian applications in nuclear medicine. It is no easy matter to fully segregate peaceful uses of nuclear technology from military or terrorist uses (such as the fabrication of dirty bombs from radioactive waste), which complicated the development of a global nuclear-power export industry right from the outset.

A ballistic missile submarine is a submarine capable of deploying submarine-launched ballistic missiles (SLBMs) with nuclear warheads. These submarines became a major weapon system in the Cold War because of their nuclear deterrence capability. They can fire missiles thousands of kilometers from their targets, and acoustic quieting makes them difficult to detect (see acoustic signature), thus making them a survivable deterrent in the event of a first strike and a key element of the mutual assured destruction policy of nuclear deterrence. Many ballistic missile submarie policies also include provisions for nuclear first strike as well. For this reasons, 70% of nuclear warheads in the USA are carried by ballistic missile submarines.

The deployment of ballistic missile submarines is dominated by the United States, Russia (following the collapse of the Soviet Union) and China. Smaller numbers are in service with France, the United Kingdom and India.