Nuclear Non-Proliferation Treaty (NPT)
The cornerstone of international nuclear governance. Signed 1968, entered into force 1970, extended indefinitely in 1995.
What It Does
The NPT creates a two-tier world:
- Nuclear weapons states (NWS) — the P5: US, USSR/Russia, UK, France, China. They agree (a) not to transfer nuclear weapons or technology to non-nuclear states, and (b) to pursue disarmament in good faith (Article VI).
- Non-nuclear weapons states (NNWS) — all other signatories. They agree never to develop or acquire nuclear weapons, and to accept IAEA safeguards on all nuclear activities.
Peaceful nuclear energy is explicitly permitted under Article IV, for all parties — this is a core bargain that has complicated enforcement ever since (Iran, Iraq, North Korea all used “peaceful program” cover).
The 1970 Watershed
The ISIS survey identifies 1970 as the decisive turning point in proliferation history. Before NPT entry into force, many European and developed countries were actively considering nuclear weapons. After 1970, very few new programs began, and the number of countries with serious programs declined. The NPT created a powerful international norm — not absolute, but significant.
Known Gaps and Failures
- Non-signatories with weapons: India, Pakistan, Israel, and North Korea were never NPT signatories (or withdrew). They are not bound by its rules and all possess weapons.
- North Korea: Signed the NPT, then withdrew in 2003. Tested its first weapon in 2006.
- India: Never signed; maintains its right to pursue weapons outside the treaty framework. India’s 1998 tests violated the spirit but not the letter of NPT (it was not a signatory). India is not a member of the Nuclear Suppliers Group (NSG), which was founded in 1974 specifically in response to India’s Smiling Buddha test.
- The disarmament gap: The nuclear weapons states have never come close to fulfilling Article VI. This asymmetry — non-nuclear states are bound, nuclear states face no meaningful enforcement — is the treaty’s central legitimacy problem.
CTBT (Comprehensive Test Ban Treaty)
A complementary treaty opened for signature September 1996. Bans all nuclear test explosions. Cannot formally enter into force until ratified by 44 specific states, of which 8 have not done so: China, India, Pakistan, North Korea, Israel, Iran, Egypt, and the United States. As of 2026, the CTBT remains unratified by the US (Senate rejected in 1999).
Structural Connections
The NPT’s core bargain — peaceful energy in exchange for no weapons — directly sets up the prisoners-dilemma logic of proliferation: individual states have incentives to defect (pursue weapons secretly) even when collective restraint produces the better outcome.