Ukraine-Russia: What will Russia do if Finland and Sweden join Nato?

"The main aim is a new Iron Curtain from the Barents to the Black Sea,” Russian state TV presenter Olga Skabeyeva claimed, following reports of Finland’s plans to apply for membership of Nato.

Her comments, however, were not referring to Finland’s intentions, indicating inevitable wider implications to the country’s Nato membership.

“The main beneficiary here is America and [Joe] Biden,” she insisted.

Finland’s decision to apply for membership of the military alliance goes against everything that Russia wants, removing part of its physical buffer zone between it and the West. And the Kremlin has reacted accordingly, warning on Thursday the “radical change in the country's foreign policy” would force Russia to “take retaliatory steps, both of a military-technical and other nature, in order to stop the threats to its national security”.

A pro-Russian convoy drives with flags on their cars through Helsinki, Finland, on May 8, ahead of Victory Day on May 9 in Russia, which commemorates the Soviet Union's defeat of Nazi Germany in World War Two. Picture: Lehtikuva/AFP via Getty Images

"We will react according to the situation,” warned the ominous last line of a lengthy statement issued by Russia’s foreign ministry.

Yet it is something the Kremlin could have avoided. Finland, which has a history of Russian aggression on its territory, had no intention of joining Nato until president Vladimir Putin’s invasion of its Ukrainian neighbour.

As recently as January, Finnish Prime Minister Sanna Marin reiterated her country did not want to join the security alliance, despite being told by Nato secretary-general Jens Stoltenberg just a few weeks earlier the “door was open” to Finnish membership. However, early last month, she noted “everything had changed” since Russia attacked Ukraine.

NATO expansion since 1997.

Ms Marin knew the comment would antagonise Russia.

“Finland should be prepared for all kinds of actions from Russia,” she said at the time.

Russia’s initial reasoning for the invasion was to "demilitarise and de-Nazify Ukraine". However, that was quickly followed by wanting to ensure Ukraine’s neutrality, due to it feeling unsafe from the "threat” of the West.

That Ukraine – among others, but as its arguably most important buffer zone – did not join Nato was one of Russia’s main demands at the start of the war.

Dmitry Medvedev, deputy chairman of Russia's Security Council, and one of Putin’s closest allies, previously went as far as to claim that if Sweden and Finland joined the alliance, then Russia would deploy nuclear weapons and hypersonic missiles in the Baltics.

Luke March, personal chair of post-Soviet and comparative politics and deputy director of the Princess Dashkova Russian Centre at Edinburgh University, said the form of Russia’s “frothing paranoia” in reaction to membership is unpredictable. But he said the country would inevitably use the situation to reinforce the efforts to mobilise the population for a longer war. He also claimed there may soon be some “military sabre-rattling” along the Finnish border.

“Russia will react to this as the victim,” he said. “There will be no reference to any defensive rationale for those countries joining Nato, but it will be seen as an aggressive move against Russia, part of Russia’s longer term encirclement by Nato and part of Russia’s longer-term, supposedly defensive, conflict with the West.

"There will be a lot of negative, warmongering statements on Russian TV, perhaps re-iterating a nuclear threat, to present Russia as strong and Nato a paper tiger.”

Previous distance between Finland and Nato has in recent years morphed into a closer working relationship – and the country has increasingly looked to the West for support.

A Russian plane was suspected of violating Finnish airspace earlier this month, while Finnish government websites were attacked by hackers during Ukrainian president Volodymyr Zelensky’s video address to its Parliament. Earlier this week Prime Minister Boris Johnson visited Helsinki to sign a deal that would see the UK go to Finland’s aid, including with military support, in the event of an attack on the country.

Veteran president Sauli Niinisto, who has previously been admired for his ability to bridge the divide between East and West and was once pictured playing ice hockey with Mr Putin, has wanted to continue cordial relations with Russia in a bid to maintain stability in the region. He has previously shown grit in refusing to bow down to Russia, however, such as in condemning Russia’s 2014 annexation of Crimea as illegal.

His stance has now changed dramatically, with the president calling for the country to apply to join Nato "without delay". The decision will ultimately be taken before Parliament, though it is expected it will have political support.

And if Finland joins Nato, it looks likely Sweden will follow suit. According to the latest results from pollster Novus, published on Wednesday, 53 per cent of Swedes are now in favour of joining Nato. However, the proportion who believe that Sweden should join if Finland joins, is even higher – a clear majority at 64 per cent. It is expected Sweden will make a similar announcement to that of Finland in the coming weeks.

Finland’s relationship with Russia, with which it shares an 800-mile border, is long and complicated.

Previously part of the Russian empire, it declared independence in 1917. However, during the Second World War, Russia invaded and a brutal battle ensued, known as the Winter War. Finland managed to stave off a full-scale attack, with the conflict ending in the signing of a treaty in 1940. However, Finland made some concessions to ensure peace – including ceding some land in the east to Russia, as well as agreeing a neutral stance, which continued throughout the Cold War.

Looking back on an interview with president Niinisto published at the end of last year, his words show why Finland would want to join the alliance.

“There’s an old saying in Finland that comes from history, which is that a Cossack — Cossack means a Russian soldier — takes everything, which is loose,” Mr Niinisto was quoted as saying. “I think people from that time, those centuries [of conflict between Finland and Russia] learnt in practice. So you have to be firm with your position.”