Controlling the Atom

One of the most significant international agreements that attempted to address the spread of nuclear weapons is the Non-Proliferation Treaty (NPT). This treaty is an attempt to limit the spread of nuclear weapons.

Under the terms of the NPT, the nations with nuclear weapons are committed not to sell them or aid in their development. Similarly, the non-nuclear states pledge not to acquire nuclear weapons or the technology to manufacture them. To date 185 nations have signed the NPT. The International Atomic Energy Agency (IAEA) governs the inspection of their facilities.

In 1996, the world renewed the treaty indefinitely. Major non-signers of the NPT include India, Pakistan, Cuba, and Israel.

In addition to the NPT, another major treaty towards arms control is the Comprehensive Test Ban Treaty (CTBT), which has been signed by 150 countries. It completely bans all testing of nuclear weapons in the atmosphere, underwater or below ground. Efforts toward this treaty have been underway since the 1960s. However, like the NPT, it has several major non-signers.

Some treaties, including the Antarctic Treaty, the Treaty of Tlatelolco, and the Outer Space Treaty, have sought to control the places where nuclear weapons can be deployed. Although the NPT limits the possession of nuclear weapons, none of these treaties limit the number of weapons nor have they led to disarmament.

There have been several arms-limitation treaties; Strategic Arms Limitation Treaty (SALT), the Vladivostok Agreement, and SALT II. In 1988, the United States and the Soviet Union signed the Intermediate-range Nuclear Forces Treaty (INF), which broke new ground by eliminating an entire class of nuclear missiles.

Gorbachev and Bush sign the START treaty
Gorbachev and Bush sign the START treaty

This treaty was followed by the Strategic Arms Reduction Treaty (START), which was signed on July 31, 1991, after almost ten years of difficult negotiations. However, with the breakup of the Soviet Union five months later, four independent states with strategic nuclear weapons came into existence—Belarus, Kazakhstan, Russia, and Ukraine. Through the Lisbon Protocol, signed in 1992, all four states became parties to the START I treaty. The treaty did not enter into force until these new states ratified the treaty and signed the NPT as non-nuclear states. Belarus, Kazakhstan, and Ukraine have removed all their nuclear warheads.

Bush and Yelstin sign the START II treaty
Bush and Yelstin sign the START II treaty

The START I treaty was followed by START II. After much delay, the treaty was finally ratified by the Russians in April 2000. The United States had ratified the treaty in 1996. By the end of the treaty's reduction timetable, the total number of strategic warheads could not exceed 3,500. By the end of 2002, no MIRVed ICBMs were allowed to be deployed. The treaty also limits the number of warheads on SLBMs, which can remain MIRVed.

Presidents Obama and Medvedev after signing the Prague Treaty.
Presidents Obama and Medvedev after signing the New START Treaty.

In 2010, the New Strategic Arms Reduction Treaty (New START) was signed in Prague by the United States and Russia. New START replaced the 1991 START I treaty, which expired December 2009, and superseded the 2002 Strategic Offensive Reductions Treaty (SORT), which terminated when New START entered into force. This treaty capped accountable deployed strategic nuclear warheads and bombs at 1,550, down approximately 30 percent from the 2,200 limit set by SORT and down 74 percent from the START-accountable limit of 6,000.