Finland's former prime minister says Russia could retaliate against his country for joining NATO, but it's well prepared

• Finland is close to joining NATO in light of Russia's invasion of Ukraine.
• Former PM Alexander Stubb said Russia may retaliate — likely in the form of a cyberattack — in response, but Finland is prepared.

Finland's former prime minister said Russia could target his country for joining NATO, but that it was well prepared for such a scenario.

Alexander Stubb, Finland's prime minister between 2014 and 2015, has long pushed for Finland to join the military alliance.

In a phone interview with Insider on Thursday, he spoke about how Finland is now closer than ever to joining thanks to Russia's invasion of Ukraine, and how Russia may respond to its membership.

Russian threats

Stubb noted that Putin had previously threatened NATO with "military-technical measures," meaning a mixture of cyber and more conventional military attacks.

For Finland, "this most probably means cyberattacks," Stubb said.

Finland experienced a cyberattack when Ukrainian President Volodymyr Zelenskyy spoke to the Finnish parliament last Friday, though the country did not say who was behind that attack.

The country also said a Russian state aircraft may have breached its airspace on the same day.

"So we expect these kinds of actions," Stubb said."But we are quite well prepared."

Finland has one of Europe's biggest militaries relative to its size, and "we have one of the strongest air forces in Europe," Stubb said.

Russia has threatened Finland with "serious military and political consequences" if it tries to join NATO.

But Stubb waved off those threats, saying he doubts Russia would mount any serious attack on Finland because "Russia's military has been so weak in Ukraine already."

Russia has largely botched its invasion of Ukraine, having lost a high number of troops — including some of its most elite and specialized — in the face of staunch Ukrainian resistance, which Russia did not expect.

But Stubb warned that when it comes to Russian President Vladimir Putin, nothing should be taken as an "empty threat."

Finland's preparations

Stubb said a response from Russia would most likely come when Finland applies to join NATO, but before it becomes a member. NATO members are well protected, as Article 5 of the group's charter states that an attack on one member is an attack on all of them.

For this reason, "Finnish political leadership has been quite active in getting implicit security guarantees from NATO member states" during this interim period, Stubb said.

"I think they have been quite successful in doing that — things that they can't say out publicly, obviously, but our president doesn't just fly to Washington, DC, to have a coffee with the [President Joe] Biden one week after the war starts," he said.

Stubb was referring to Finnish President Sauli Niinistö's meeting with Biden in early March, where the men agreed to work more closely on security but did not publicly outline their plans.

Joining NATO

Finland has moved closer to joining NATO since Russia invaded Ukraine on February 24.

Finland shares an 800-mile-long border with Russia, and was part of the Russian Empire before later gaining independence. It was then invaded by the Soviet Union in 1939 but successfully fought back.

Public opinion in Finland has, for the first time, shifted to a majority supporting joining the alliance, and Prime Minister Sanna Marin said Wednesday that the country would decide whether it will pursue membership "within weeks, not within months."

Stubb said the only thing that could delay Finland's NATO application would be an attack from Russia, but that he doesn't think such a scenario likely to happen.

Stubb told Insider he has been an "advocate of Finnish NATO membership for the better part of 30 years."

He said that as prime minister, he repeatedly tried to rouse public support to join NATO, but was dismissed for reasons including the country's history with neutrality and the fear of Russian retaliation.

But Stubb noted that Finnish support for NATO membership "changed pretty much overnight on the 24th of February when Putin and Russia attacked Ukraine."

"Putin has only himself to thank, you know, I should probably be grateful to Putin, as a strong advocate of Finnish NATO membership," he said. "I was giving up hope."

He said the most important argument for Finland joining NATO is that it would "increase our security."

"The train has left the station," he said. "Finland is on board and our final destination is the headquarters of NATO in Brussels."