Finland became the 31st member of NATO on Tuesday — a once-unthinkable step that significantly changes the security landscape in Europe.
Why it matters: Finland's membership more than doubles NATO's borders with Russia and formally ends Helsinki's decades of official nonalignment. It's also a blow to Russian President Vladimir Putin who, in launching the Russian invasion of Ukraine, vowed to block the alliance's eastward expansion.
- It's the alliance's ninth enlargement since its founding in 1949.
- NATO Secretary-General Jens Stoltenberg sent a message to Moscow while officially welcoming Finland into the alliance: "President Putin wanted to slam NATO's door shut. Today we showed the world that he failed, that aggression and intimidation do not work. Instead of less NATO, he has achieved the opposite: more NATO. And our door remains firmly open."
- Finland President Sauli Niinistö said it was a "great day for Finland" but also an important day for the security and the stability of the alliance.
Driving the news: Finland, along with Sweden, applied for NATO membership "hand in hand" after Russia invaded Ukraine last year.
- The two Nordic neighbors had hoped to become members at the same time, but Hungary and Turkey have held up Sweden's application. It's unclear if and when it may move forward. All NATO members must approve new members.
- Stoltenberg said he looked forward to welcoming Sweden "as soon as possible." He also noted that Finland's accession process had been the fastest in NATO's modern history.
What they're saying: "When Putin launched his brutal war of aggression against the people of Ukraine, he thought he could divide Europe and NATO. He was wrong," President Biden said in a statement on Tuesday.
- "Today, we are more united than ever. And together—strengthened by our newest Ally Finland—we will continue to preserve transatlantic security, defend every inch of NATO territory, and meet any and all challenges we face," he added.
Moscow has warned Finland and Sweden against joining the alliance.
- Putin's spokesperson Dmitry Peskov earlier Tuesday called Finland's NATO accession an “encroachment on Russia’s security” that would require Russia to take unspecified countermeasures.
- Putin had previously said that Russia had no "territorial differences" with Finland or Sweden, so it was "up to them" whether they joined — but Russia would respond to any deployments of NATO military units or infrastructure to their territories.
- The Russian embassy in Sweden issued an even more pointed warning last week, saying on Facebook that any "new members of the enemy block will become a legitimate target" of "Russia's retaliatory measures," including those of military nature.
Go deeper: Listen to the Axios Today podcast, where host Niala Boodhoo talks about Finland becoming the 31st member of NATO.
Editor's note: This story has been updated with additional details throughout.
