The potential consequences of Finland and Sweden joining NATO

OPINION:

In response to Russia’s invasion of Ukraine, it is reported that Finland and Sweden intend to apply for NATO membership as early as June.

Both countries have consistently adhered to a policy of neutrality between Russia and the West, and admitting these new members to NATO would have major ramifications for European security. Moscow issued a veiled threat in response, warning the two Nordic countries that Russia would need to “rebalance the situation” should they join NATO. While admitting new states into the alliance may vindicate a desire to punish Russia for its brutal campaign in Ukraine, the potential short- and long-term strategic consequences of expanding NATO at this moment could prove catastrophic.

Western leaders need to consider the possibility that Russian President Vladimir Putin could order a preventive attack on Finland and/or Sweden before official NATO membership is granted. For years Moscow made clear that it viewed NATO enlargement as a threat to Russia’s national security. Russia backed up its claim on three separate occasions in which it used military force ostensibly to prevent a bordering state from joining NATO — invading Georgia in 2008, annexing Crimea and supporting pro-Russian rebels in the Donbas in 2014, and invading Ukraine in 2022. Although Sweden does not border Russia, Finland shares an 830-mile border ranging from the Gulf of Finland in the south to the Arctic in the north.

Would Russia seriously consider an attack on Finland or Sweden? While it may seem unlikely, the West should not underestimate the possibility that Mr. Putin, feeling isolated, backed into a corner, and under a time constraint, may make an otherwise rash decision. Russia may not have the current wherewithal to conduct a full-scale invasion of Finland or Sweden, but it could launch limited strikes on military targets, attempt to seize small portions of Finnish or Swedish territory, or conduct grey zone operations, such as cyberattacks.

Absent the possibility of an attack on Finland or Sweden, extending NATO membership will have repercussions for the United States. Russia would likely increase its military forces on Finland’s border, the Baltic Sea and in the Arctic. U.S. leaders will feel pressured to respond in kind, increasing U.S. troops in Europe, which already number 100,000. With tensions extremely high, further military deployments increase the chance for miscalculation. A NATO-Russia conflict, with its potential for nuclear escalation, would prove devastating on a global scale.

With new NATO members requiring unanimous approval by the national parliaments of all 30 existing members, Congress is obligated to consider if admitting Finland and Sweden serves the U.S. national interest. Article 5 of the Washington Treaty requires that the United States comes to the defense of a NATO ally should they be attacked. This means a de-facto extension of the U.S. nuclear deterrent — essentially requiring the United States to consider a nuclear strike on Russia if it attacked a NATO member. Given the ramifications of such a decision, the promise of defending two more countries, including one that shares a long border with Russia, must not be made lightly.

Finland and Sweden’s policy of military nonalignment has long been viewed as a stabilizing factor in Northern Europe, but Mr. Putin’s senseless invasion of Ukraine has shattered Europe’s sense of security. However, Russia’s inability to subjugate Ukraine after seven weeks of heavy fighting indicates that Moscow’s conventional strength is weaker than previously thought. Russia’s lackluster performance may in fact signal to Finland and Sweden that they can maintain their neutrality and the ability to deter Russia without joining NATO.

While both countries are ultimately free to apply for NATO membership, the United States may approve or deny the extension of its security commitment based on how their membership serves U.S. interests. As the United States shifts its attention to the Indo-Pacific and long-term strategic competition with China, Washington should encourage its wealthy and capable European allies to take primary responsibility for the continent’s defense. The United States must assess if burden-shifting in Europe is helped or hindered by adding Finland and Sweden to NATO before accepting their bids for membership.

U.S. policymakers have a responsibility to the American people to pursue a foreign policy that increases their security and prosperity. Recognition and thoughtful debate regarding the possible unintended consequences of NATO expansion is the least they can do.

• Sascha Glaeser is a research associate at Defense Priorities. He focuses on U.S. grand strategy, international security and transatlantic relations. He holds a master’s in international public affairs and a bachelor’s in international studies from the University of Wisconsin-Madison.