Russia, U.S.A., France, China, U.K., Pakistan, India, Israel

According to: https://www.armscontrol.org/factsheets/Nuclearweaponswhohaswhat at the dawn of the nuclear age, the United States hoped to maintain a monopoly on its new weapon, but the secrets and the technology for making nuclear weapons soon spread. The United States conducted its first nuclear test explosion in July 1945 and dropped two atomic bombs on the cities of Hiroshima and Nagasaki in August 1945. Just four years later, the Soviet Union conducted its first nuclear test explosion. The United Kingdom (1952), France (1960), and China (1964) followed. Seeking to prevent the nuclear weapon ranks from expanding further, the United States and other like-minded states negotiated the nuclear Nonproliferation Treaty (NPT) in 1968 and the Comprehensive Nuclear Test Ban Treaty (CTBT) in 1996.

India, Israel, and Pakistan never signed the NPT and possess nuclear arsenals. Iraq initiated a secret nuclear program under Saddam Hussein before the 1991 Persian Gulf War. North Korea announced its withdrawal from the NPT in January 2003 and has tested nuclear devices since that time. Iran and Libya have pursued secret nuclear activities in violation of the treaty’s terms, and Syria is suspected of having done the same. 

At the time the NPT was concluded, the nuclear stockpiles of both the United States and the Soviet Union/Russia numbered in the tens of thousands. Beginning in the 1970s, U.S. and Soviet/Russian leaders negotiated a series of bilateral arms control agreements and initiatives that limited, and later helped to reduce, the size of their nuclear arsenals. Today, the United States and Russia each deploy roughly 1,400 strategic warheads on several hundred bombers and missiles, and are modernizing their nuclear delivery systems.

China, India, and Pakistan are all pursuing new ballistic missile, cruise missile, and sea-based nuclear delivery systems. In addition, Pakistan has lowered the threshold for nuclear weapons use by developing tactical nuclear weapons capabilities to counter perceived Indian conventional military threats. North Korea continues its nuclear pursuits in violation of its earlier de-nuclearization pledges.

After the 1986 Reykjavik Summit between U.S. President Ronald Reagan and Soviet General Secretary Mikhail Gorbachev, the United States and the Soviet Union concluded two important nuclear arms reduction treaties: the INF Treaty (1987) and START I (1991). After the end of the Cold War, the United States and the Russian Federation concluded the Strategic Offensive Reductions Treaty (2003) and the New START Treaty (2010).

When the extreme danger intrinsic to nuclear war and the possession of nuclear weapons became apparent to all sides during the Cold War, a series of disarmament and nonproliferation treaties were agreed upon between the United States, the Soviet Union, and several other states throughout the world. Many of these treaties involved years of negotiations, and seemed to result in important steps in arms reductions and reducing the risk of nuclear war.

Key treaties:

• Partial Test Ban Treaty (PTBT) 1963: Prohibited all testing of nuclear weapons except underground.
• Nuclear Non-Proliferation Treaty (NPT)—signed 1968, came into force 1970: An international treaty (currently with 189 member states) to limit the spread of nuclear weapons. The treaty has three main pillars: nonproliferation, disarmament, and the right to peacefully use nuclear technology.
• Interim Agreement on Offensive Arms (SALT I) 1972: The Soviet Union and the United States agreed to a freeze in the number of intercontinental ballistic missiles(ICBMs) and submarine-launched ballistic missiles (SLBMs) that they would deploy.
• Anti-Ballistic Missile Treaty (ABM) 1972: The United States and Soviet Union could deploy ABM interceptors at two sites, each with up to 100 ground-based launchers for ABM interceptor missiles. In a 1974 Protocol, the US and Soviet Union agreed to only deploy an ABM system to one site.
• Strategic Arms Limitation Treaty (SALT II) 1979: Replacing SALT I, SALT II limited both the Soviet Union and the United States to an equal number of ICBM launchers, SLBM launchers, and heavy bombers. Also placed limits on Multiple Independent Reentry Vehicles (MIRVS).
• Intermediate-Range Nuclear Forces Treaty (INF) 1987: Created a global ban on short- and long-range nuclear weapons systems, as well as an intrusive verification regime.
• Strategic Arms Reduction Treaty (START I)—signed 1991, ratified 1994: Limited long-range nuclear forces in the United States and the newly independent states of the former Soviet Union to 6,000 attributed warheads on 1,600 ballistic missiles and bombers.
• Strategic Arms Reduction Treaty II (START II)—signed 1993, never put into force: START II was a bilateral agreement between the US and Russia which attempted to commit each side to deploy no more than 3,000 to 3,500 warheads by December 2007 and also included a prohibition against deploying multiple independent reentry vehicles (MIRVs) on intercontinental ballistic missiles (ICBMs)
• Strategic Offensive Reductions Treaty (SORT or Moscow Treaty)—signed 2002, into force 2003: A very loose treaty that is often criticized by arms control advocates for its ambiguity and lack of depth, Russia and the United States agreed to reduce their "strategic nuclear warheads" (a term that remained undefined in the treaty) to between 1,700 and 2,200 by 2012. Was superseded by New Start Treaty in 2010.
• Comprehensive Test Ban Treaty (CTBT)—signed 1996, not yet in force: The CTBT is an international treaty (currently with 181 state signatures and 148 state ratifications) that bans all nuclear explosions in all environments. While the treaty is not in force, Russia has not tested a nuclear weapon since 1990 and the United States has not since 1992.
• New START Treaty—signed 2010, into force in 2011: replaces SORT treaty, reduces deployed nuclear warheads by about half, will remain into force until at least 2021
• Treaty on the Prohibition of Nuclear Weapons—signed 2017, not yet in force: prohibits possession, manufacture, development, and testing of nuclear weapons, or assistance in such activities, by its parties.

In addition to formal treaties, U.S. President George H.W. Bush and Soviet President Gorbachev agreed on mutual unilateral Nuclear Disarmament, with a focus on eliminating Tactical Nukes. It is estimated that ~8,000 "atomic bombs" were removed from the arsenals as a result. Read the behind-the-scenes story here. Watch President Bush describe his initiative via televised address here

Only one country has been known to ever dismantle their nuclear arsenal completely—the apartheid government of South Africa apparently developed half a dozen crude fission weapons during the 1980s, but they were dismantled in the early 1990s.

November 7, 2018. Alarmed at what they see as disintegrating curbs on Nuclear Weapons, a bipartisan array of American experts have urged President Trump to continue work on disarmament negotiations. 

Despite the INF treaty’s flaws, they said, the United States should work to fix the accord, not walk away from it. “The INF Treaty has prevented the unchecked deployment of nuclear missiles in Europe,” stated the letter to the White House, signed by more than a dozen prominent figures in arms control, including former Secretary of State George P. Shultz and former Senators Richard Lugar and Sam Nunn. Full text: https://drive.google.com/file/d/1kdGky0NumiWz4MWwyFNirxP9NTB9a37h/view

Hans M. Kristensen, director of the Nuclear Information Project at the Federation of American Scientists where he provides the public with analysis and background information about the status of nuclear forces and the role of nuclear weapons. He published the following on October 5, 2018:

"The latest New START treaty aggregate numbers published by the State Department earlier today show a slight increase in U.S. deployed strategic forces and a slight decrease in Russian deployed strategic forces over the past six months.

The data shows that the United States and Russia as of September 1, 2018 combined deployed a total of 1,176 strategic launchers with 2,818 attributed warheads. In addition, the two countries also had a total of 399 non-deployed launchers for a total of 1,576 strategic launchers.

Combined, the two countries have reduced their deployed strategic forces by 227 launchers and 519 warheads since 2011.

The warheads counted by the New START treaty are only a portion of the total warhead numbers possessed by the two countries. The Russian military stockpile includes an estimated 4,350 warheads while the United States has about 3,800.

The release of the data comes at a particular important time when the United States and Russia are considering whether to extend the New START treaty for another five years beyond 2021 when it expires. The treaty is under attack from defense hawks in Congress and the Trump administration is weighing whether to extend New START in light of Russia’s alleged violation of other agreements.The data reaffirms that Russia, despite its modernization program, is not increasing its strategic nuclear forces but continue to limit them in compliance with the limitations of New START. In our latest Nuclear Notebook on Russia forces, we estimate that the New START limits recently caused Russia to reduce the number of warheads deployed on several of its strategic missiles.

Deployed Warheads

The data shows that the United States as of September 1 deployed 1,398 warheads on its strategic launchers. This is an increase of 48 warheads since February. Since 2011, the United States has offloaded 402 attributed warheads from its force.The 1,398 is not the actual number of warheads deployed because bombers are artificially attributed one weapon each even though they don’t carry any weapons in peacetime. The actual number of deployed warheads is closer to 1,350.

Russia was counted with 1,420 deployed strategic warheads, a reduction of 24 warheads from February, and a total of 117 attributed warheads offloaded since 2011. Russian bombers also do not carry weapons so the Russian number is probably closer to 1,370 deployed strategic warheads.These changes don’t reflect one country building up and the other reducing its forces, but are caused by fluctuations when launchers move in and out of maintenance or old launchers are retired or new ones added.

Deployed Launchers

The data shows the United States deployed 659 strategic launchers, an increase of 7 since February, and a total reduction of 223 launchers since 2011.Russia deployed 517 strategic launchers, 142 fewer than the United States. That is 10 launchers less than in February, and a total reduction of 4 launchers since 2011.

Non-Deployed Launchers

The data also shows how many non-deployed launchers the two countries have. These are either empty launchers that are in reserve or overhaul or have not yet been destroyed.The United States had 141 non-deployed launchers, which included empty ICBM silos, bombers in overhaul, and empty missile tubes on SSBNs in overhaul or refit. Since 2011, the United States has destroyed 101 non-deployed launchers.Russia was counted with 258 non-deployed launchers. This includes empty ICBM silos, empty missile tubes on SSBNs in overhaul, and bombers in overhaul. Since 2011, Russia has destroyed 86 non-deployed launchers.

Essential Verification In Troubled Times

The treaty includes an important verification system that requires the United States and Russia to exchange vast amounts of data about the numbers and operations of their strategic forces and allows them to inspect each other’s facilities.Since the treaty entered into effect in 2011, the two countries have exchanged 16,444 notifications about launcher movements and telemetry data; 1,603 since February this year.Data released by the State Department shows that U.S. and Russian inspectors have conducted a total of 277 on-site inspections of each other’s strategic forces and facilities since the treaty entered into force in 2011. So far this year, U.S. officials have inspected Russian facilities 13 times compared with 12 Russian inspections of U.S. facilities.

The combined effects of limiting deployed strategic forces and the verification activities requiring professional collaboration between U.S. and Russian officials, mean that the New START treaty has become a beacon of light in the otherwise troubled relations between Russia and the United States, far more so than anyone could have predicted in 2010 when the treaty was signed.

Other background information:

• Russia nuclear forces, 2018
• US nuclear forces, 2018
• Status of world nuclear forces, 2018
• After Seven Years of Implementation, New START Treaty Enters Into Effect

This publication was made possible by a grant from the Carnegie Corporation of New York, the John D. and Catherine T. MacArthur Foundation, the New Land Foundation, and the Ploughshares Fund. The statements made and views expressed are solely the responsibility of the author."