Key Takeaways:
Europe is rapidly rearming, with EU defence spending projected to reach €454 billion in 2026 and NATO allies committed to 5 percent of GDP by 2035, driven by the Russia-Ukraine war’s demonstration of attrition warfare and the post-Cold War industry’s inability to keep pace.
The buildup reflects classic security-dilemma logic: European governments treat Russian aggression as requiring deterrence by denial and tripwire forces, while Russia’s war-economy spending (around 7.5 percent of GDP) and fears of NATO encirclement risk fuelling a spiral.
Rearmament also serves as insurance against possible U.S. disengagement, yet it faces fragmented procurement, long production lags, nuclear-stability paradoxes and domestic political risks if weak growth forces trade-offs with the welfare state.
For decades after 1945, Europe tried to make war unthinkable through trade, shared institutions and democratic habit. Political scientists even gave the result a name: a “security community,” in Karl Deutsch’s phrase, where states stop imagining war among themselves. (1)
Now the continent is rearming, and fast. The post-Cold War “peace dividend” is gone. Governments from Scandinavia to Poland have reached the same uncomfortable conclusion: The surest way to avoid a continental war is to look ready to fight one. International relations theory has a much older worry about that logic, and it deserves a re-reading of the situation.
The Russia-Ukraine war, which began in 2022, explains most of the shift. European capitals no longer read the conflict as a border dispute. They read it as an attack on the security order the continent has depended on since 1991. The war also has shown what a large conflict consumes. Drones and cyber operations matter, but attrition dominates the fighting: shells, spare parts, long supply lines and a steady supply of soldiers. Europe’s defense industry, allowed to shrink for 30 years, could not keep pace, and governments noticed.
The budgets show the change. EU members spent €418 billion on defense in 2025, about 2.2% of the bloc’s GDP, and projections put 2026 at €454 billion. (2) That lifts the EU above NATO’s old 2% benchmark. The 2025 NATO summit in The Hague then moved the goalposts. Allies agreed to spend 5% of GDP on defense by 2035, with at least 3.5% for core military needs and up to 1.5% for related areas such as infrastructure and cyber defense. (3) More than 32% of EU defense spending now goes to investment, mainly equipment and research, comfortably above the 20% benchmark. (4)
But Europe’s defense market remains fragmented. Governments buy national systems in small batches, which keeps costs high and makes it harder to share ammunition and spare parts. Collaborative projects made up only 24% of equipment procurement in 2025. (5)
New production lines need factories, skilled workers and long-term contracts before they deliver anything. Even well-funded armies face years of waiting, and that gap is when deterrence is most exposed. Geography shapes each country’s response. Poland aims to field the largest army in Europe by 2030, with 500,000 troops, including 200,000 high-readiness reservists, Defense Minister Władysław Kosiniak-Kamysz said in May. (6) Estonia, Latvia and Lithuania are building a joint Baltic Defence Line of bunkers, anti-tank ditches and other barriers, including up to 600 bunkers in Estonia alone. (7) Rail Baltica, a European-gauge railway linking Poland with the Baltic states, now doubles as a route for moving NATO troops quickly. (8)
Strategists would recognize two ideas at work. Allied battlegroups in the Baltics are a Schelling-style tripwire: too small to stop an invasion alone, but certain to draw in larger forces. (9) The fortifications aim at deterrence by denial, making an attack so costly that it is not worth trying. (10) Germany’s Operationsplan Deutschland extends the logic into civilian life. It casts the country as a hub for allied forces heading east and folds civilian agencies and infrastructure into military planning. (11)
Sweden and Finland, NATO’s newest members, are preparing households. Sweden has mailed a war-preparedness booklet to 5.2 million homes, and Finland has launched a preparedness website. (12) French President Emmanuel Macron has refused to rule out any step, including sending troops, that might prevent a Russian victory. He has described the ambiguity as deliberate, calling it “strategic ambiguity.” (13)
What pushes this along is Russia’s shift to a war economy. Military and war-related spending reached about 16 trillion rubles in 2025, or 7.5% of GDP, according to the Stockholm International Peace Research Institute. (14) Economists call it military Keynesianism: Growth, wages and political stability now lean on arms production. That makes ending the war harder for Moscow than it looks, because peace could bring a recession. The 2026 budget trims planned military spending to 14.9 trillion rubles, or 6.3% of GDP, but the institute says the budget will probably be amended. (15)
European intelligence services worry that a Russia satisfied in Ukraine would turn to NATO next. Denmark’s defense intelligence service has said Russia could be ready for a large-scale European war within about five years if the fighting ends and NATO does not match its buildup. (16) Moscow could test Article 5 with sabotage, hybrid pressure or a limited grab near the Suwałki Gap. That is a judgment about intentions, and intentions are hard to read. Russian forces are stretched in Ukraine, and analysts disagree about how soon they could threaten anyone else.
The security dilemma, described by John Herz and refined by Robert Jervis, holds that steps one state takes to feel safe can make its neighbors feel threatened, and they arm in response. (17)
Jervis distinguished two worlds. In a deterrence world, the adversary is aggressive and weakness invites attack, so arming is wise. In a spiral world, the adversary is mainly insecure, and arming feeds the fear that drives it. (18) Moscow’s own account is a spiral story: NATO enlargement as encirclement. Realist scholars such as John Mearsheimer find it persuasive. (19) Most European governments reject it, noting that Russia’s 2022 invasion came before the rearmament, not after it.
The honest position is that the two worlds are hard to tell apart in real time, and a wrong guess is costly either way. Europe has bet on deterrence, but it should keep asking what Moscow sees when it looks west. Alliance politics adds a second tension. Stephen Walt argued that states balance against threats, not merely against power, and few things look more threatening to Europeans than a large, armed, revisionist neighbor. (20) But Glenn Snyder identified the central dilemma of alliances: the fear of abandonment by a patron versus the fear of entrapment in its quarrels. (21) Washington’s pivot toward the Middle East and the Indo-Pacific, along with the unpredictability of its politics, has sharpened European fears of abandonment. Rearmament is partly an insurance policy against a United States that may do less.
Mancur Olson and Richard Zeckhauser predicted long ago that in alliances the largest contributor carries a disproportionate share while smaller partners free-ride. (22) For decades Europe was the free rider, and Americans are now reaping the political result. The U.S. will keep the nuclear umbrella and its role as NATO’s final backstop, but the tanks, troops and air defenses will increasingly carry European flags.
Nuclear weapons complicate the picture. Britain and France are the only European NATO members with independent arsenals, and France is beginning to open its deterrent to allies. In March 2026, Macron announced a “forward deterrence” framework that would let allies join French nuclear exercises and allow temporary deployments of nuclear-capable French aircraft on their soil. (23)
Snyder also coined the “stability-instability paradox”: When nuclear war is too dangerous to risk, lower-level aggression becomes more tempting because the stakes seem too small to justify escalation. (24) That is the logic behind worries about gray-zone attacks on NATO’s edge. Sabotage and ambiguous incursions are designed to stay below the threshold that would trigger Article 5, and conventional strength is what makes that gamble unattractive.
Rearming means choosing to spend billions on shells and fighter jets, and that money will come at least partly out of the welfare state Europeans value. If eurozone growth stays weak, populist parties will make the guns-versus-butter argument their own, which could strain EU cohesion and public support for NATO commitments. Constructivists would add that the change is also one of identity. Germany, long described as a “civilian power,” now plans for war on its own territory. (25) Whether voters accept that new self-image will matter as much as the budget lines.
Europe’s security rested on assumptions that no longer hold. The open question is endurance across 10 years of budget fights and election cycles. Voters will be asked to pay for a threat that, if deterrence works, never materializes. Leaders who can explain that to their publics will matter as much as any new brigade.
Endnotes:
Karl W. Deutsch et al., Political Community and the North Atlantic Area: International Organization in the Light of Historical Experience (Princeton, N.J.: Princeton University Press, 1957).
European Defence Agency, “EU defence spending: €418 billion in 2025, projected to €454 billion in 2026,” July 16, 2026, https://eda.europa.eu/news-and-events/news/2026/07/16/eu-defence-spending—418-billion-in-2025–projected-to–454-billion-in-2026. The 2.2% and 2.4% of GDP figures and the finding that 23 member states spent at least 2% of GDP on defense in 2025 come from the same release. Full report: EDA, Defence Data 2025-2026, https://eda.europa.eu/docs/default-source/eda-publications/2026-eda_defencedata_webpublic.pdf.
NATO, “The Hague Summit Declaration,” June 25, 2025, https://www.nato.int/cps/en/natohq/official_texts_236705.htm. The declaration commits allies to at least 3.5% of GDP annually for core defense requirements and up to 1.5% for areas including critical infrastructure, networks, civil preparedness, innovation and the defense industrial base.
EDA, “EU defence spending,” July 16, 2026 (investment share of more than 32% against the 20% benchmark). See also Defence Data 2025-2026, as summarized in “EU Defence Spending hits €418 BN in 2025, set for €454 BN in 2026,” European Defence Review, July 16, 2026, https://www.edrmagazine.eu/eu-defence-spending-hits-e418-bn-in-2025-set-for-e454-bn-in-2026.
EDA, Defence Data 2025-2026, as summarized by European Defence Review (collaborative expenditure was 24% of equipment procurement in 2025), https://www.edrmagazine.eu/eu-defence-spending-hits-e418-bn-in-2025-set-for-e454-bn-in-2026. EDA’s own summary also cites fragmentation and limited program integration as obstacles to turning research into deployable capabilities: https://community.era.gv.at/news-items/eda-defence-data-2025-2026-show-that-eu-rd-defence-spending-continues-to-increase/.
“Poland ready to host more US troops, defence minister says,” Polskie Radio, May 6, 2026, https://polskieradio.pl/395/7784/Artykul/3683119,poland-ready-to-host-more-us-troops-defence-minister-says. Prime Minister Donald Tusk made a similar pledge in August 2026: “Poland will soon have Europe’s largest army, Tusk pledges,” Kyiv Independent, https://kyivindependent.com/poland-will-soon-have-europes-largest-army-tusk-pledges/.
Estonian Ministry of Defence, “Baltic Defence Line,” https://www.kaitseministeerium.ee/en/policies-and-development-defence-capability/national-defence-planning/baltic-defence-line; and “Baltic nations prepare 600-strong bunker defensive line with Russian threat in mind,” Breaking Defense, February 2024, https://breakingdefense.com/2024/02/baltic-nations-prepare-600-strong-bunker-defensive-line-with-russian-threat-in-mind/.
“Bunkers to Fortify Baltic Borders,” Center for European Policy Analysis, https://cepa.org/article/bunkers-to-fortify-baltic-borders/; and “The Baltics: Estonia, Latvia and Lithuania – An overview,” Friedrich Naumann Foundation for Freedom, https://freiheit.org/central-europe-and-baltic-states/episode-1-baltics-estonia-latvia-and-lithuania-overview.
Thomas C. Schelling, Arms and Influence (New Haven, Conn.: Yale University Press, 1966).
Glenn H. Snyder, Deterrence and Defense: Toward a Theory of National Security (Princeton, N.J.: Princeton University Press, 1961). The Baltic states describe their defense line as an application of NATO’s “deterrence by denial” posture; see the Estonian Ministry of Defence page cited above.
Bundeswehr, “Stresstest für den Operationsplan Deutschland,” https://www.bundeswehr.de/de/organisation/operatives-fuehrungskommando-der-bundeswehr/stresstest-operationsplan-deutschland-5863010; and “Operationsplan Deutschland: Wie verteidigen wir unser Land?,” https://www.bundeswehr.de/de/selbstverstaendnis/geschichte-bundeswehr/territoriales-fuehrungskommando-der-bundeswehr/operationsplan-deutschland-5703688. The plan itself is classified.
Swedish Civil Contingencies Agency (MSB), If Crisis or War Comes (2024). Distribution and Finland’s website: “Sweden, Finland urge residents to be ready for war,” Agence France-Presse, Nov. 18, 2024, https://english.ahram.org.eg/News/535458.aspx. Finland’s guidance covers power cuts, water outages, telecommunications disruptions and military conflict: Sana Noor Haq, CNN, Nov. 18, 2024, https://kesq.com/news/national-world/cnn-world/2024/11/18/stockpile-nappies-medication-baby-food-nato-members-sweden-and-finland-advise-citizens-on-how-to-survive-war/.
“Macron not ruling out sending Western troops to Ukraine,” Agence France-Presse, Feb. 27, 2024, https://english.ahram.org.eg/News/518449.aspx; and “Macron Floats Ukraine Troop Deployment if Frontline Breached,” The Defense Post, May 2, 2024, reporting an interview with The Economist, https://thedefensepost.com/2024/05/02/macron-ukraine-troop-deployment/amp/.
Julian Cooper, “A Budget for a Fifth Year of War: Military Spending in Russia’s Budget for 2026,” SIPRI Insights on Peace and Security No. 2026/01, March 2026, https://www.sipri.org/publications/2026/sipri-insights-peace-and-security/budget-fifth-year-war-military-spending-russias-budget-2026.
Cooper, “A Budget for a Fifth Year of War.”
Danish Defence Intelligence Service, assessment of the Russian threat to Denmark, February 2025, as reported in “Russia Gearing Up for Full-Scale War Against NATO, Denmark Says,” Kyiv Post, https://kyivpost.com/post/47032. The agency said it saw no concrete Russian plans for a war against a NATO country.
John H. Herz, “Idealist Internationalism and the Security Dilemma,” World Politics 2, no. 2 (January 1950): 157–80; Robert Jervis, “Cooperation Under the Security Dilemma,” World Politics 30, no. 2 (January 1978): 167–214.
Robert Jervis, Perception and Misperception in International Politics (Princeton, N.J.: Princeton University Press, 1976), chap. 3.
John J. Mearsheimer, “Why the Ukraine Crisis Is the West’s Fault,” Foreign Affairs 93, no. 5 (September/October 2014): 77–89.
Stephen M. Walt, The Origins of Alliances (Ithaca, N.Y.: Cornell University Press, 1987).
Glenn H. Snyder, “The Security Dilemma in Alliance Politics,” World Politics 36, no. 4 (July 1984): 461–95.
Mancur Olson Jr. and Richard Zeckhauser, “An Economic Theory of Alliances,” Review of Economics and Statistics 48, no. 3 (August 1966): 266–79.
“Macron to boost nuclear arsenal, involve European allies in doctrine change,” Reuters, March 2, 2026, https://www.bairdmaritime.com/security/weaponry/macron-to-boost-nuclear-arsenal-involve-european-allies-in-doctrine-change; and “Inside Macron’s new deterrence strategy: 8 European allies, 1 French nuclear button,” The Associated Press, March 3, 2026, https://www.clickondetroit.com/news/world/2026/03/03/inside-macrons-new-deterrence-strategy-8-european-allies-1-french-nuclear-button/.
Glenn H. Snyder, “The Balance of Power and the Balance of Terror,” in The Balance of Power, ed. Paul Seabury (San Francisco: Chandler, 1965), 184–201.
Hanns W. Maull, “Germany and Japan: The New Civilian Powers,” Foreign Affairs 69, no. 5 (Winter 1990/91): 91–106.
About Aishwarya Sanjukta Roy Proma
Aishwarya Sanjukta Roy Proma is a lecturer in the Department of International Relations at the University of Rajshahi. Her scholarly expertise spans South Asian politics, refugee and migration dynamics, democratic governance, state reform, and global geopolitics. She actively contributes to policy-oriented research and international discourse; her work addresses critical regional and transnational challenges across South Asia and the broader global arena.
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