After tensions and a years-long wait, Sweden ends its neutrality and joins NATO

It was a process that took nearly two years after objections by two NATO members, but Sweden has now officially become the 32nd member of the military alliance. It's a move that sees it end decades of post-World War Two neutrality.

Soldiers of the Swedish Armed Forces during a military exercise in February. Sweden has joined NATO. Source: Getty, AFP / Jonathan Nackstrand

Sweden has formally joined NATO as the 32nd member of the transatlantic military alliance, ending decades of post-World War Two neutrality as concerns about Russian aggression in Europe have spiked following Russia's 2022 invasion of Ukraine.

Swedish Prime Minister Ulf Kristersson and Secretary of State Antony Blinken presided at a ceremony in which Sweden's "instrument of accession" to the alliance was officially deposited at the State Department.

"This is a historic moment for Sweden. It's historic for the alliance. It's history for the transatlantic relationship," Blinken said. "Our NATO alliance is now stronger, larger than it's ever been."

US Secretary of State Antony Blinken and Swedish Prime Minister Ulf Kristersson (right) greet US Ambassador to Türkiye, Jeff Flake (left), during the NATO ratification ceremony at the US State Department, as Sweden formally joins. Source: Getty, AFP / Andrew Caballero-Reynolds

Kristersson wrote in a social media post that "we are therefore a safer country."

The Swedish Prime Minister will visit the White House and then be a guest of honour at President Joe Biden's State of the Union address to Congress.

The White House said that having Sweden as a NATO ally "will make the United States and our allies even safer."

NATO Secretary-General Jens Stoltenberg described it as "a historic day."

The Swedish flag will be raised outside the military organisation's headquarters in Brussels on Monday. Stoltenberg underscored that the Nordic country "now enjoys the protection granted under Article 5, the ultimate guarantee of allies' freedom and security."

Article 5 of NATO's treaty obliges all members to come to the aid of an ally whose territory or security is under threat. It has only been activated once – by the United States after the 11 September, 2001, attacks – and is the collective security guarantee that Sweden has sought since Russia invaded Ukraine.

"Sweden's accession makes NATO stronger, Sweden safer and the whole alliance more secure," Stoltenberg said. He added that the move "demonstrates that NATO's door remains open and that every nation has the right to choose its own path."

The Swedish flag will be raised outside the military organisation's headquarters in Brussels on Monday Source: Getty, AFP / John Thys

Sweden, along with Finland, which joined NATO last year, both abandoned long-standing military neutrality that was a hallmark of the Nordic states' Cold War foreign policy after Russia invaded Ukraine in early 2022.

Biden, in his speech to Congress, is expected to cite Sweden's accession to NATO as evidence that Russian President Vladimir Putin's intent to divide and weaken the alliance has failed as a direct result of the Ukraine invasion. And, the Democratic president is expected to use Sweden's decision to join to step up calls for reluctant Republicans to approved stalled military assistance to Ukraine as the war enters its third year.

Biden and his NATO counterparts have vowed that Ukraine will join one day, too.

Sweden's membership had been held up due to objections by NATO members Türkiye and Hungary. Türkiye expressed concern that Sweden was harbouring and not taking enough action against Kurdish groups that it regards as terrorists, and Hungary's populist President Viktor Orban has shown pro-Russian sentiment and not shared the alliance's determination to support Ukraine.

After months of delay, Türkiye ratified Sweden's admission earlier this year, and Hungary did so this week.