Finland and Sweden want to join NATO. Here’s how it works and what comes next

Sweden’s Prime Minister Magdalena Andersson followed suit on Monday, confirming her government had decided to begin the process of seeking NATO membership.

Finland’s move to seek to join the alliance requires a vote in parliament, but given the support of the ruling government, that hurdle is expected to be passed comfortably. In Sweden, the move was debated in parliament on Monday and there is broad support for joining NATO, but the government does not need parliamentary consent to move ahead.

“When we look at Russia, we see a very different kind of Russia today than we saw just a few months ago,” Finnish Prime Minister Sanna Marin said Sunday. “Everything has changed when Russia attacked Ukraine. And I personally think that we cannot trust anymore there will be a peaceful future next to Russia.”

Joining NATO is “an act of peace [so] that there will never again be war in Finland in the future,” Marin said.

Her Swedish counterpart, Andersson, said Monday: “To ensure the safety of Swedish people, the best way forward is to join NATO together with Finland.”

When asked when exactly the country will hand in the application, she said it could it happen either Monday, Tuesday or Wednesday this week, adding that it needs to be done in coordination with Finland.

The announcements were met with support from leaders in almost all NATO nations. US Secretary of State Antony Blinken told reporters “the United States would strongly support the NATO application by either Sweden or Finland should they choose to formally apply to the alliance. We will respect whatever decision they make.”

What comes next?

NATO has what it calls an “open door policy” on new members — any European country can request to join, so long as they meet certain criteria and all existing members agree.

A country does not technically “apply” to join; Article 10 of its founding treaty states that, once a nation has expressed interest, the existing member states “may, by unanimous agreement, invite any other European State in a position to further the principles of this Treaty … to accede.”

NATO diplomats told Reuters that ratification of new members could take a year, as the legislatures of all 30 current members must approve new applicants.

The process may not be without hurdles; Turkey’s President Recep Tayyip Erdogan said Friday he was not looking at both countries joining NATO “positively,” accusing them of housing Kurdish “terrorist organizations.”

Finnish President Sauli Niinistö told CNN he was “confused” by those comments on Sunday, claiming Erdogan had been far more receptive to the idea in a telephone conversation between the two leaders a month ago.

“I think that what we need now is a very clear answer. I’m prepared to have a new discussion with President Erdogan about the problems he has raised,” Niinistö said.

But NATO Secretary General Jens Stoltenberg attempted to allay concerns about Turkey’s stance, saying Sunday the country “has made it clear that their intention is not to block membership.” Blinken also said Sunday he was “very confident that we will reach consensus.”

In the meantime, both countries will have to rely on its current allies and partners for security guarantees, rather than Article 5 — the clause which states an attack against one NATO nation is an attack against all, and which triggers a collective response in that event.

Sweden and Finland have received assurances of support from the United States and Germany should they come under attack, while British Prime Minister Boris Johnson signed mutual security agreements with his Finnish and Swedish counterparts last week.

What does NATO membership entail?

Article 5 has been a cornerstone of the alliance since NATO was founded in 1949 as a counterweight to the Soviet Union.

The point of the treaty, and Article 5 specifically, was to deter the Soviets from attacking liberal democracies that lacked military strength. Article 5 guarantees that the resources of the whole alliance — including the massive US military — can be used to protect any single member nation, such as smaller countries who would be defenseless without their allies. Iceland, for example, has no standing army.

Former Swedish leader Carl Bildt told CNN he doesn’t see new big military bases being built in either country should they join NATO. He said that joining the alliance would likely mean more joint military training and planning between Finland, Sweden and NATO’s 30 current members. Swedish and Finnish forces could also participate in other NATO operations around the globe, such as those in the Baltic states, where several bases have multinational troops.

“There’s going to be preparations for contingencies as part of deterring any adventures that the Russians might be thinking of,” Bildt said. “The actual change is going to be fairly limited.”

Why haven’t Finland and Sweden already joined NATO?

While other Nordic countries like Norway, Denmark and Iceland were original members of the alliance, Sweden and Finland did not join the pact for historic and geopolitical reasons.

Both Finland, which declared independence from Russia in 1917 after the Bolshevik revolution, and Sweden adopted neutral foreign policy stances during the Cold War, refusing to align with the Soviet Union or the United States.

Sweden opted to maintain its neutral status after the war ended.

Finland’s neutrality has historically proved more difficult, as it shared a massive border with an authoritarian superpower.

A Finno-Soviet treaty known as the Agreement of Friendship, signed in 1948 and extended on occasion through the decades, prohibited Finland from joining any military alliance considered hostile to the USSR, or from allowing a Western attack through Finnish territory.

To keep the peace, Finns adopted a process some call “Finlandization,” in which leaders acceded to Soviet demands from time to time. The term was coined during the Cold War and has been applied to other countries in which a superpower exerts control over smaller neighboring states.

Both countries’ balancing acts effectively ended with the collapse of the Soviet Union. Sweden and Finland joined the European Union together in 1995 and gradually aligned their defense policies with the West, while still avoiding joining NATO outright.

Each country had different reasons for avoiding signing up for NATO pact in tandem with the EU.

For Finland, it was more geopolitical. The threat for Russia is more tangible thanks to the two countries’ shared 830-mile border.

“Finland has been the exposed country, and we’ve been the protected country,” Bildt told CNN’s Christiane Amanpour in a joint interview alongside former Finnish prime minister Alexander Stubb.

While an independent nation, Sweden’s geography puts it in the same “strategic environment” as its liberal democratic neighbors, Bildt said. Finland and Sweden have enjoyed a close partnership for decades, with Stockholm viewing its decision to refrain from joining NATO as a way to help keep the heat off Helsinki. Now, however, Sweden is likely to follow Finland’s lead.

“We share the idea that close cooperation will benefit both of us,” current Swedish Prime Minister Magdalena Andersson said at a news conference last month alongside her Finnish counterpart Marin.

How Russia’s invasion changed everything

Sweden and Finland have been inching towards the West on security issues since joining the EU in 1995, shortly after the end of the Cold War. But Russia’s invasion of Ukraine dramatically accelerated that process, pushing Sweden and Finland to pull the trigger on NATO membership.

If the Kremlin was willing to invade Ukraine — a country with 44 million people, a GDP of about $516 million, and an armed forces of 200,000 active troops — what would stop Putin from invading smaller countries like Finland in Sweden?

“Everything changed when Russia invaded Ukraine,” Finnish premier Marin said in April. “People’s mindset in Finland, also in Sweden changed and shifted very dramatically.”

Since the Russian invasion of Ukraine in February, public support for joining NATO in Finland has leaped from around 30% to nearly 80% in some polls. The majority of Swedes also approve of their country joining the alliance, according to opinion polls there.

“Our NATO membership was decided on the 24th of February, at 5 o’clock in the morning, when Putin and Russia attacked Ukraine” former Finnish leader Stubb told CNN. “Finland and Sweden would not have joined without this attack.”

Russia, Swedish Defense Minister Peter Hultqvist told CNN, wants “real influence in the security choices in Europe.”

“They want an influence over the countries in the neighborhood. And that is totally unacceptable for Sweden.”

How has Russia reacted?

Russia lambasted the decision by Finland and Sweden. Its deputy Foreign Minister Sergei Ryabkov said Monday that the move would be a “mistake” with “far-reaching consequences,” according to state news agency TASS.

That followed similar threats from high-ranking Moscow officials. Kremlin spokesperson Dmitry Peskov said that “NATO expansion does not make the world more stable and secure” after the announcement. He added that Russia’s reaction would depend on “how far and how close to our borders the military infrastructure will move.”

Russia currently shares about 755 miles of land border with five NATO members, according to the alliance. Finland’s accession would mean that a nation with which Russia shares an 830-mile border would become formally militarily aligned with the United States.

The addition of Finland and Sweden would also benefit the alliance, which would frustrate Russia. Both are serious military powers, despite their small populations.

Russian President Vladimir Putin said Monday that “Russia has no problems with these states,” adding that the expansion of NATO “does not pose a direct threat to Russia.”

“But the expansion of military infrastructure into this territory will certainly cause our response,” he added at the Collective Security Treaty Organization in Moscow. “We will see what it will be based on the threats that will be created for us.”

However, Bildt and Stubb, the former Swedish and Finnish premiers, believe that so far, Russia’s response has been relatively muted.

“The Kremlin sees Finnish and Swedish NATO membership as a Nordic solution, and in that sense, not a radical threat,” said Stubb. “We’re not too worried.”

Stubb and Bildt said they believe Moscow ultimately sees the two countries as reliable neighbors, despite their decision to join a Washington-backed alliance.

“The fact that Finland and Sweden are part of the West doesn’t come as a surprise,” said Bildt.

Why does Russia loathe NATO?

Putin sees the alliance as a bulwark aimed at Russia, despite the fact that it had spent much of the post-Soviet years focusing on issues like terrorism and peacekeeping.

Before Putin invaded Ukraine, he made clear his belief that NATO had edged too close to Russia and should be stripped back to its borders of the 1990s, before some countries that either neighbor Russia or were ex-Soviet states joined the military alliance.

The irony is that the war in Ukraine has, effectively, given NATO a new purpose.

“Article 5 is back in the game, and people understand that we need NATO because of a potential Russian threat,” Stubb said in an interview with CNN before the invasion.

This story has been corrected to reflect that Sweden’s government does not need parliament’s consent to pursue membership in NATO.