Sweden’s final hindrance to joining NATO was eliminated on Monday after hold-out Hungary’s ratification, concluding 200 years during which Stockholm’s military self-reliance enabled it to build a global brand as an impartial peacemaker and human rights champion. Russia’s invasion of Ukraine in February 2022 provoked Swedes with a pivotal choice: join NATO or run the danger of standing alone against an increasingly aggressive near neighbor.

NATO membership might appear uncontroversial, but some Swedes worry it signals a fundamental shift in identity. “Sweden’s historically strong voice on the issues of peace and disarmament seems to be going silent,” said Kerstin Bergea, chairperson of the Swedish Peace and Arbitration Society, a prominent peace movement since 1883. “The cause of peace has been part of our DNA,” she said.

From U.N. Secretary-General Dag Hammarskjold’s steps to promote peace in 1960s Congo to Hans Blix’s role as chief U.N. weapons inspector in the lead-up to the Iraq war, Sweden’s neutrality has allowed it to play an effective role in global conflicts, often punching above its weight.

Sometimes that came in the shape of blistering criticism of Western policy, such as former Prime Minister Olof Palme’s comparison of U.S. bombings in the Vietnam War to mankind’s most destructive atrocities, including Nazi Germany’s death camps, damaging diplomatic relations with Washington for years. Veteran diplomat Jan Eliasson, a former foreign minister and U.N. deputy secretary-general said he could mediate in some global conflicts “because Sweden was neutral”.

Like many Swedes of his generation, Eliasson stated he was proud of his country’s reputation as a moral force, epitomized by Palme, a vocal advocate of South Africa’s anti-apartheid struggle who was assassinated on a Stockholm street in 1986. While neighbor Norway, a founding member of NATO, has strengthened its role as a peace broker, NATO skeptics fear joining the alliance will limit Sweden’s options and force it to toe a standard line with its allies.

Securing Turkey’s support for its NATO membership has already led Stockholm to take a stricter stance on Kurdish militants battling for a homeland on the borders of Turkey, Syria, and Iraq and resume arms exports to Ankara previously stopped as a result of human rights concerns. Membership in nuclear-armed NATO also sits uncomfortably with Sweden’s support for nuclear disarmament.

Sweden’s neutrality formed as a response to catastrophic wars – mainly against Russia – in the 18th and early 19th centuries, and its procedures have always been a mix of principle and pragmatism. It supplied Nazi Germany with strong iron ore during World War Two and, during the Cold War, secretly exchanged intelligence with the United States.

In recent decades, Sweden has inclined closer to NATO – in part because its military was slashed after the collapse of the Soviet Union – and has contributed to missions in Afghanistan, Kosovo, Libya, and Iraq.

Close partnership, however, is now seen as inadequate. NATO’s Article 5 guarantees that an invasion on any member is considered an attack on all. “From a Swedish perspective, this is about buying insurance,” Barbara Kunz at the Stockholm International Peace Research Institute (SIPRI) said.

Opinion polls have turned in recent years and now show robust backing for NATO membership in the nation of 10 million, primarily as neighbor Finland, which shares a long border with Russia, has already joined.

“We were seeing right in front of our eyes … horrible military aggression taking place against another country, and we, unfortunately, were in a position of having a relatively unprepared defense,” Eliasson expressed.

“Aggression, war crimes, Finland and democracy. That was enough for me.”