Finnish prime minister Sanna Marin said on Thursday that Russia’s invasion of Ukraine would lead to a significant shift in the debate over Finland’s potential participation in NATO.

“Finland is not currently facing an immediate military threat, but it is also now clear that the debate on NATO membership in Finland will change,” Marin said, according to Finland’s YLE news outlet. She added, however, that a potential Finnish accession to NATO would require the broad support of Finns, who have historically been skeptical of the military alliance.

Finland and neighboring Sweden, who have both charted independent foreign policies for decades, are expected to attend NATO’s summit on the ongoing Russian-Ukrainian war on Friday. That summit was called by the Baltic states under Article IV of the North Atlantic Treaty, which provides a mechanism for the member states to convene when “the territorial integrity, political independence or security of any of the parties is threatened.”

While Finland is not a NATO member, the country’s leaders have harshly criticized Russian leader Vladimir Putin for his recognition of the two separatist Donbass republics and Russia’s subsequent invasion of Ukraine. “The mask has now come off,” President Sauli Niinisto said in reference to Putin’s earlier claim that the Kremlin had no intention of invading its western neighbor.

Finland’s international status has remained highly unusual since its independence from the Russian Empire after the First World War. Finland was invaded by the Soviet Union in late 1939. In the ensuing “Winter War,” Finnish troops repeatedly annihilated invading Soviet columns, leading to a settlement in which Finland gave up a section of its border but retained its independence.

Finland maintained its independent position throughout the Cold War, sometimes serving as a neutral ground between the United States and the Soviet Union. A summit held in the capital in 1975 produced the “Helsinki Final Act,” a landmark human rights agreement that reinforced detente between the two great powers until 1979.

The expansion of NATO has angered the Kremlin, which originally attacked Ukraine over concerns that the country was aligning itself politically with the European military bloc. A key Russian demand in the run-up to the conflict was for NATO to publicly commit to end its expansion and disavow future Ukrainian membership. However, this was a pledge that NATO officials refused to make, arguing that no external country could have a veto on Ukraine’s security decisions.

Trevor Filseth is a current and foreign affairs writer for the National Interest.

Image: Reuters.