Three consecutive review conferences have now ended without consensus. When delegates to the Nuclear Non-Proliferation Treaty (NPT) Review Conference gathered in New York earlier this year, they were supposed to assess the health of a treaty that has shaped the nuclear order for more than half a century. Instead, four weeks of negotiations ended without an agreed substantive outcome. A dispute between the United States and Iran over language concerning Tehran’s nuclear program became one of the final obstacles, adding 2026 to the failed conferences of 2015 and 2022 (Flatoff & Kimball, 2026).
The treaty itself has not disappeared. Its restrictions remain in force, and states continue to describe the NPT as central to preventing nuclear proliferation. But outside the review process, another form of nuclear security is becoming increasingly important: protection built around alliances, defense agreements and the arsenals of nuclear-armed partners.
That distinction matters. The NPT asks states without nuclear weapons to remain without them. Security guarantees attempt to answer the question that follows: what protects those states when nuclear deterrence still shapes international security? As confidence in multilateral arms control comes under pressure, governments may increasingly look toward powerful partners rather than treaty negotiations for reassurance.
The NPT will remain an important part of the nuclear order, but it increasingly exists alongside a less uniform system of security guarantees. Treaty obligations are nearly universal; access to credible protection is not. As alliances and defense arrangements take on greater importance, the countries left without such guarantees may become the clearest sign of how the nuclear order is changing.
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The third failure matters because of the disagreements underneath it, not the paragraph that exposed the deadlock (Flatoff & Kimball, 2026). The United States insisted on language addressing Iran’s nuclear program, while Tehran objected both to being singled out and to the removal of earlier language condemning US and Israeli attacks on safeguarded Iranian nuclear facilities. Yet conference president Do Hung Viet stressed that difficulties extended beyond that dispute. Delegations also remained divided over nuclear disarmament, nuclear sharing, the conflicts in Ukraine and the Middle East, and several other parts of the draft.
This does not make the NPT irrelevant. Review conferences have failed to produce consensus documents before, and states continued in 2026 to affirm support for the treaty’s three pillars of non-proliferation, disarmament, and peaceful nuclear energy. The problem is that consensus has become increasingly difficult to translate into common action. The last successful Review Conference was in 2010; attempts in 2015, 2022 and
2026 all ended without an agreed substantive outcome (Arms Control Association, 2026; Flatoff & Kimball, 2026).
That distinction is important for the wider nuclear order. The NPT can still establish rules against proliferation without resolving the security pressures that make nuclear weapons attractive in the first place. When governments doubt that multilateral agreements alone can protect them from nuclear coercion or conventional attack, the question of who provides security outside the treaty becomes harder to ignore.
That alternative is already taking shape in the Middle East. In August, Saudi Arabia, Türkiye and Pakistan signed the Makkah Joint Defence Agreement, committing each country to regard an armed attack against one as an attack against all (Saudi Press Agency, 2026). The pact has since moved beyond a political declaration. The three governments have since established mechanisms for political and military coordination, while their military leaderships have discussed deeper intelligence sharing and capability integration (Reuters, 2026).
Pakistan’s participation gives the agreement a nuclear dimension that its text does not clearly define. It is the only nuclear-armed member of the pact and, unlike Saudi Arabia and Türkiye, sits outside the NPT. Yet the agreement does not explicitly place either
country under a Pakistani nuclear umbrella. Yet the agreement does not explicitly place either country under a Pakistani nuclear umbrella, while Pakistan has described the arrangement as defensive (Pakistan Ministry of Foreign Affairs, 2026). Ambiguity is nevertheless important: a non-nuclear state can deepen its security relationship with a nuclear-armed partner without acquiring nuclear weapons itself or establishing a formal nuclear-sharing arrangement.
For Saudi Arabia in particular, this adds another layer to a security architecture historically centered on the United States. The Makkah Pact does not replace Washington, and Türkiye remains protected separately through NATO. In fact, it provides another source of deterrence at a time when regional confidence in US protection has been questioned. In that sense, the pact illustrates how security guarantees can multiply around the NPT without requiring states to abandon the treaty itself.
Alliance-based nuclear protection is hardly a new phenomenon. NATO has relied on extended nuclear deterrence for decades, while the United States provides similar assurances to allies in Asia (NATO, 2026; United States Department of State, 2024).
In June, NATO’s Nuclear Planning Group again described the alliance’s strategic nuclear forces as the “supreme guarantee” of allied security and committed to
strengthening nuclear planning and modernizing its capabilities (NATO, 2026). Washington maintains similarly explicit extended-deterrence commitments in the Indo-Pacific, including to Japan (United States Department of State, 2024). This complicates the idea of a straightforward transition from rules to umbrellas. The two systems have long existed alongside one another. Every NATO member is also a party to the NPT, and NATO itself argues that its nuclear posture is compatible with the treaty.
For countries such as Germany, Japan or South Korea, remaining non-nuclear does not mean living without nuclear deterrence. Their security arrangements allow them to stay within the non-proliferation regime while relying on the arsenal of an ally (NATO, 2026).
What appears to be changing is the weight placed on those guarantees. NATO is strengthening its nuclear planning, while US allies in the Indo-Pacific continue to deepen their extended-deterrence consultations with Washington (NATO, 2026; United States Department of State, 2024).
The nuclear order is therefore becoming more dependent on relationships that the NPT itself does not provide. For states already inside these alliances, those guarantees can reduce the security pressures associated with remaining non-nuclear. For those outside
them, the same reassurance is much harder to obtain. The same logic is becoming visible in physical infrastructure.
A September agreement between the United States, Denmark and Greenland allows Washington to expand Pituffik Space Base and establish additional defense areas at Narsarsuaq and Mestersvig (White House, 2026). The agreement specifically links US access to the defense of North America, including the development of the Golden Dome missile defense system. Greenland therefore illustrates another side of the umbrella: protection can depend not only on promises of retaliation, but on access to sensors, bases and defensive systems embedded within an alliance network.
The NPT is therefore unlikely to vanish from the nuclear order. Its rules remain central to limiting proliferation, but rules alone cannot provide every state with the same degree of security. Three failed review conferences make that limitation harder to overlook while defense agreements and strategic umbrellas continue to develop around them. The danger is a nuclear order divided between states protected by powerful allies and those expected to trust the rules without receiving comparable reassurance. The NPT may remain the common rulebook, even as security increasingly depends on who is standing beside you.
