The Stockholm Initiative

In June 2019, Sweden launched the Stockholm Initiative for Nuclear Disarmament (SIND), a 16-country coalition formed on the anniversary of the 1970 Nuclear Non-Proliferation Treaty. In its first published declaration, signatory ministers hailed the successes of the Non-Proliferation Treaty (NPT) while warning about the growing role for nuclear weapons amid deteriorating global security concerns. Alongside calls to preserve the 2015 Iran Nuclear Deal, the initiative also called for changes to nuclear deterrence doctrines. It further promoted “negative security assurances,” whereby nuclear-armed states pledge not to use nuclear weapons against non-nuclear states.  Representing the host country, Swedish Prime Minister Stefan Löfven described SIND as a “seminal political initiative” offering “clear progress” in the United Nations’ endeavors to limit nuclear weapons.

The Foundations of Neutrality

Sweden’s founding role in this initiative is no coincidence. For over two centuries, Sweden has avoided direct participation in wars and cultivated a doctrine of military non-alignment until it joined NATO in 2024. The country’s policies on staying out of conflicts trace back to the Napoleonic Wars. At the time, Sweden elected French field marshal Charles XIV John as king following a major military defeat to Russia in 1809. The Swedish aristocracy had hoped the new monarch would help reclaim Finland by aligning with Napoleon’s coalition. Instead, Charles XIV John joined forces with Russia in 1812, securing the annexation of Norway in the later post-war settlement. During the Concert of Europe period, non-alignment became central to the security posture of the Swedish-Norwegian union. After the dissolution of that union in 1905, Stockholm maintained neutrality through both World Wars as Europe descended into its largest-ever conflicts.

Neutrality in Practice until the Interwar Period

The First World War accelerated Sweden’s transition from military non-alignment toward formal neutrality. This development was spurred by the European workers’ movement, whose first geopolitical breakthrough came with Russia’s 1917 exit from World War I after the Bolshevik Revolution. Socialist pacifist sentiment had similarly altered the trajectory of Swedish national politics a few years prior: During the Courtyard Crisis of 1914, the Social Democratic Party organized mass protests that successfully stymied plans to build a flotilla of armored boats. During the First World War and the interwar period, defense expenditures declined to historic lows. Stockholm simultaneously pursued legalistic neutrality measures. As one example, this included a blanket ban on foreign submarines in its territorial waters, while diplomatic tensions emerged with the United States over the ethics of arms exports.

The Second World War and Cold War

The Second World War however, exposed the contradictions of Swedish neutrality. Prominently, this included extensive iron ore supply to Nazi Germany, Wehrmacht transit through Swedish territory, and the extradition of Baltic soldiers to the USSR. Navigating the Cold War, Stockholm doubled down on neutralist ideals, prohibiting munitions exports to active war zones and channeling anti-nuclear diplomatic ventures through the UN. Echoing the posture established in 1812, Moscow viewed Swedish  foreign policy with approval, while Soviet state media described the Social Democrats as “guarantors of neutrality.”

The 2022 Rupture

Since the end of the Cold War, the Swedish government has gradually softened Stockholm’s policy of non-alignment. Sweden joined the European Union in 1994 and equipped the domestically produced JAS Gripen fighter jet with NATO-compatible systems. The watershed moment came with Russia’s 2022 full-scale invasion of Ukraine, the largest act of military aggression in Europe since the Second World War. Despite initially describing NATO accession as “destabilizing,” Sweden’s Prime Minister Magdalena Andersson led the Social Democratic party’s security-policy reversal. The country subsequently applied for membership in the defensive alliance in May 2022. Following the 2022 general election, Prime Minister Ulf Kristersson announced a grand “reorienting” of Swedish foreign policy. The process culminated in NATO membership in 2024. A defining feature of this strategic about-face was the simultaneous abandonment of neutrality by Sweden and Finland. Proponents like Finland’s President Sauli Niinistö argued that a coordinated move toward NATO would reduce the risk of either country being singled out by Russia.

From Disarmament to Deterrence

Sweden’s reversed stance on NATO demonstrates a wider security realignment. For the first time in almost a century, Stockholm exported major arms to an active warzone in the form of military aid to Ukraine. In 2026, Sweden opened negotiations with French military manufacturer Naval Group to purchase four armored frigates. Stockholm also embarked on discussions in the same year with the French government about the possibility of nuclear sharing. By contrast, the Stockholm Initiative for Nuclear Disarmament has occupied a less prominent place in Swedish foreign policy under the Kristersson government. One public indication for that is the absence of declarations resembling the initiative’s 2019 statement on the government’s website. During the initial diplomatic gridlock surrounding Sweden’s NATO application, Turkey and Hungary delayed ratification for months. In the meantime, Stockholm relied on the very kind of nuclear security guarantees the SIND originally sought to limit. Beyond Sweden, SIND also weakened internationally. New Zealand and Indonesia withdrew from the pact in 2023. Two other signatories, Kazakhstan and Ethiopia, refused to put their name to a formal condemnation of Russia’s war in Ukraine.  In 2024, the UK Center for the Study of Existential Risk called the SIND “largely moribund.”

New Models Inside NATO

Sweden is a newcomer to NATO still in the process of finding its footing within the alliance. With non-alignment and neutrality increasingly relegated to history, Stockholm may turn to leading NATO members for strategic inspiration: While the US remains the alliance’s dominant military power, Sweden neighbor just across the Baltic Sea, Poland, tops the list in defense spending relative to GDP. Under Prime Minister Donald Tusk, Warsaw has withdrawn from the 1997 Ottawa Mine Ban Treaty and become a major military player in Central Europe. Irrespective of the precise path the country will embark on, Stockholm’s grappling with the breakdown of regional security suggests that idealistic disarmament commitments are currently taking a back seat to pragmatic military deterrence. Sweden’s transformation from a champion of nuclear disarmament to a NATO member in less than five years illustrates how rapidly security doctrines can shift during periods of geopolitical instability.