Nuclear Treaties - Will They Hold Up in Our Changing Political World?

There are several major international agreements whose core purpose is to limit the spread, testing, and potential use of nuclear weapons, though none can absolutely guarantee non‑use as will be noted below.

The last nuclear test took place in North Korea on September 3, 2017. The previous longest period without a detonation was between May 30, 1998, when Pakistan conducted its last test, and October 9, 2006, when North Korea conducted its first. The 2017 nuclear test caused a 6.3 magnitude earthquake in Punggye village, which resulted in the collapse of several civilian buildings.

The Core global treaties

Treaty on the Non‑Proliferation of Nuclear Weapons (NPT): In force since 1970 with more than 190 parties, it is the central global agreement. 

Recognizes five nuclear‑weapon states (U.S., Russia, U.K., France, China).
Requires all other members not to acquire nuclear weapons.
Commits nuclear states to pursue negotiations toward disarmament.
Places non‑nuclear states under international safeguards to ensure nuclear energy is used only for peaceful purposes.

Comprehensive Nuclear‑Test‑Ban Treaty (CTBT): Opened for signature in 1996, it bans all nuclear test explosions in any environment, aiming to freeze qualitative improvement and signal political commitment against nuclear use, though it has not yet formally entered into force because some key states have not ratified it.

Treaty on the Prohibition of Nuclear Weapons (TPNW): Entered into force in 2021. It completely bans development, possession, deployment, and use or threat of use of nuclear weapons for its parties; it is the first treaty to categorically outlaw nuclear weapons as a class of arms. Nuclear‑armed states, however, have not joined.disarmament.unoda+1

Bilateral arms‑control treaties (mainly U.S.–Russia)

Agreements such as the Strategic Arms Reduction Treaties (START/New START) and the now‑collapsed INF Treaty limited the number and types of deployed strategic nuclear weapons and banned entire classes of missiles, with verification measures to reduce the risk of sudden escalation or large‑scale use.

Nuclear‑weapon‑free zones

Several regional treaties declare whole regions free of nuclear weapons and include negative security assurances (promises by nuclear states not to use or threaten nuclear weapons against those regions), for example:

Treaty of Tlatelolco (Latin America and the Caribbean)
Treaty of Rarotonga (South Pacific)
Treaty of Bangkok (Southeast Asia)
Treaty of Pelindaba (Africa)
Treaty of Semipalatinsk (Central Asia)

These aim to reduce the chance of nuclear weapons being stationed or used in those regions. None of these agreements can absolutely prevent nuclear use, especially because some nuclear‑armed states are outside key treaties or have left certain agreements.

But, taken together, they create legal, political, and verification frameworks that:

Restrain the number and spread of nuclear weapons.
Make testing and preparations for use more visible.
Strengthen global norms that nuclear use would be illegitimate and catastrophic.