Policy planning reflected that belief. Governments prepared for escalation management, energy disruption, and post-conflict instability not for sustained deterrence or a prolonged, high intensity war. This failure was neither accidental nor confined to a single capital or political party. It was the result of long-standing policy choices, alliance design decisions, and a shared belief that restraint could substitute for credible deterrence.

A Long Arc of Under-Resourcing

The NATO alliance arrived at this moment after more than a decade of deliberate under-investment. Under Presidents Barack Obama and later Joe Biden, U.S. defense policy emphasized escalation avoidance, fiscal restraint, and risk management over capacity, readiness, and industrial depth. Deterrence became a matter of signaling rather than a consistent force structure.

This trajectory did not change meaningfully during President Donald Trump’s first term. Budgetary turbulence, government shutdowns, continuing resolutions, and inherited top lines constrained structural change. Europe took its cues from Washington as strategic restraint aligned with European politics. Risk aversion, energy accommodation with Russia, and the belief that diplomacy could compensate for declining hard power. This was publicly validated when Obama was awarded the Nobel Peace Prize, not for altering U.S. strategy, but largely for reaffirming a posture Europe favored. The signal was unmistakable: restraint would be rewarded, not penalized.

Alliance Design and the Shock of 2022

NATO functioned exactly as designed. After the Cold War, the United States explicitly asserted its leadership and structured the alliance accordingly. Command arrangements, rank hierarchies, and decision-making processes ensured that Washington always held the most senior voices in the room—and an effective pocket veto.

The shock in 2022 was not that Europe took the lead, but that President Biden was so timid as to reinforce Russian risk assessments. Escalation anxiety, combined with under-resourced deterrence, produced caution when decisiveness was needed. Europe, constrained by years of deferred defense investment and structural energy dependence, lacked both the capacity and the political will to move faster than Washington. The result was paralysis by design: American restraint set the ceiling, European limitations set the floor, and the Western alliance’s action was trapped in between.

Europe Attempts to Lead

European leaders deserve credit for attempting to break the paralysis when the scale of Russian aggression became unmistakable. Boris Johnson effectively accelerated the accession of Finland and Sweden into NATO by signing bilateral security guarantees that would have placed NATO forces on the ground and triggered Article 5 through cascading alliance obligations. It was a brilliant realist move, anchoring deterrence in forward commitment rather than process. Overcoming a Europe constrained by alliance structure, capacity, and the limits of American political cover.

Energy Sovereignty as a Deterrence Variable

A critical and under-appreciated failure was Europe’s abandonment of energy sovereignty. Years of policy choices have left European economies structurally dependent on Russian hydrocarbons at precisely the moment when deterrence required resilience. In 2024, the EU bloc purchased approximately €21.9 billion ($23.5 billion) worth of fossil fuels from Russia—exceeding the €18.7 billion ($20 billion) it reported allocating to Ukraine in financial aid over the same period. Climate change was elevated as the dominant strategic threat, displacing hard-power competitors such as Russia and China in threat prioritization and in efforts to defend Ukraine from Russian invasion. That disordering of risk mattered.

Europe compounded its vulnerability by dismantling reliable nuclear capacity before a dependable replacement baseload was in place. Rather than sequencing decarbonization alongside firm alternatives, several states removed nuclear generation while relying on Russian gas to bridge the gap. This was not a technical error but a strategic one.

Deterrence is weakened by dependence and strengthened when leverage is denied. The destruction of the Nord Stream pipelines did not create Europe’s vulnerability; it exposed and accelerated its resolution. It removed Russia’s most potent instrument of coercive leverage over Europe. The act dismantled a dependency that had distorted European decision-making and narrowed the range of credible responses.

The Burden-Sharing Reality

The deeper problem exposed by the war is not under-spending, but misaligned responsibility. Europe accounts for nearly 44 percent of NATO’s combined GDP yet contributes 32 percent of alliance defense spending and a smaller share of high-end industrial capacity. That disparity was sustainable only so long as American support was unconditional and inexhaustible. It is not.

Fixating on President Trump’s demand for fairness obscures this structural reality. Trump did not create alliance stress; he exposed it. The core issue is that NATO has evolved into a system in which the United States bears disproportionate escalation risk while Europe enjoys disproportionate security benefits. In any conflict in which U.S. and European equities are asymmetric, that imbalance creates credibility problems—and adversaries can see them clearly.

Europe has begun to wake up. Defense budgets are rising, industrial capacity is being rebuilt, and strategic rhetoric has hardened. However, it took Vladimir Putin’s war—his willingness to use force at scale on Europe’s borders—to force a reckoning that European leaders had long postponed.

Interests, Narratives, and Credibility

Deterrence rests on perception of strength and credibility. When responsibility, risk, and capability are asymmetric, resolve is questioned. Credibility erodes quietly, long before it collapses publicly.

The uncomfortable truth is that U.S. and European interests are not perfectly aligned. Europe increasingly speaks the language of realism. Deterrence, balance, and forward defense, while framing policy through a liberal narrative of norms, process, and institutional legitimacy. That mismatch is not illegitimate, but it becomes dangerous when it masks unequal contributions and obscures who bears the true costs of failure.

Necessary Correction

The solution is neither retrenchment nor recrimination. It is a shift toward genuine Regional Shared Deterrence: a model in which European states meet NATO obligations proportionate to their economic weight, rebuild industrial capacity at scale, restore energy sovereignty, and assume visible responsibility for regional defense outcomes. That, in turn, would allow the United States to lead decisively without carrying the alliance alone—restoring credibility through aligned incentives and shared risk.

Ukraine did more than halt a Russian invasion. By refusing to collapse, it shattered Western assumptions and disrupted plans built around convenience rather than genuine deterrence. That disruption has exposed a simple truth: deterrence that is under-resourced by design and shared only in rhetoric will fail when tested. Whether this moment produces a strategic correction—or merely another cycle of improvisation—will determine the next crisis long before it arrives.

Kirk Fansher is a retired Colonel, Senior Fellow at the National Institute for Deterrence Studies, and Editor at Global Security Review. A Yale graduate and U.S. Naval War College alum, he has published extensively on nuclear posture, extended deterrence, and burden sharing. The views expressed are his own.

Ukraine and the Failure of Western Assumptions was originally published on Global Security Review.

The national security strategy outlines the president’s strategic vision and serves as the closest approximation to a U.S. grand strategy. It orients the POTUS’ goals and associated efforts in foreign and defense policy within the executive branch and informs Congress of the POTUS’ priorities and direction. The NSS declares what is important to America—its national interests, goals, and priorities—and emphasizes how the President envisions the use of America’s diplomatic, informational, economic, military, and technological instruments of power to achieve or service those interests. The 2025 National Security Strategy is not the most comprehensive ever produced; that distinction belongs to the President’s first NSS in 2017.

The 2025 NSS identifies three core national interests that collectively shape U.S. strategy. First, it is the “balance of power,” which focuses on U.S. security and emphasizes preventing any rival from gaining regional or global dominance that could threaten U.S. sovereignty or freedom of action. Second, a predisposition to non-interventionism, which reflects a desire to limit U.S. involvement in long-lasting or discretionary foreign wars, emphasizing restraint, burden-sharing, and deterrence over “fruitless ‘nation-building’ wars.” Third, economic security, a key strategic goal, which requires the United States to maintain its position as the world’s leading economy through balanced trade, secure access to essential resources, reindustrialization, energy security, and mutually beneficial economic ties with other countries. Collectively, these interests reveal a strategy that prioritizes American strength and strategic stability over “forever wars,” while recognizing that economic vitality and security are inseparable from national power.

Only a strong nuclear deterrent will ensure these core national interests are both protected and advanced. The core idea of 2025 NSS is “peace through strength,” asserting credible military power and the fear it projects as the best safeguard against conflict amid geopolitical turbulence and great-power competition. This NSS espouses a more realist disposition, unapologetically relying on deterrence to project strength in a world fraught with nuclear weapon expansion. President Reagan reminded us in 1986 that “Nations do not mistrust each other because they are armed; they are armed because they mistrust each other.”

The 2025 NSS clearly states on page three, “We want the world’s most robust, credible, and modern nuclear deterrent.” This is the engine of a U.S. balance of power policy—acting to prevent other states or coalitions of states from achieving dominant power over the U.S., thereby maintaining a balance between stability and security. Moreover, the NSS emphasizes that deterrence depends on maintaining U.S. military “overmatch.” An abundant, modern, and resilient nuclear arsenal not only provides the military advantage sought but also does so at a lower cost than a conventionally armed force with equivalent destructive capability.

Next, instead of open-ended overseas wars or nation-building, the 2025 NSS frames military engagement as justified only when U.S. core interests are directly threatened. This predisposition to non-interventionism requires maximum deterrence strategies to prevent regional conflicts from escalating into large-scale wars that could “come to our shores, [which] is bad for American interests.”

Moreover, empowering and enabling allies and partners—removing imperial perceptions of American behavior—by letting them lead, investing in their capabilities, and treating them as co-architects rather than subcontractors signals that America is not trying to dominate outcomes but to share responsibility. This creates economic value through burden sharing and arms sales, while fostering an equally shared commitment to security goals and deterrence. Capacity building is not short-sighted; it is a long-term investment in partnerships that advance the balance of power without relying solely on American taxpayers.

The 2025 NSS further stresses that economic security and vitality—one of President Trump’s central goals—requires a sustained focus on deterrence to prevent war in the Indo-Pacific and beyond. By creating the strategic space for economic expansion, successful deterrence enables reinvestment in the very capabilities that preserve it. This dynamic not only offers a long-term sustainment pathway for America’s nuclear deterrent force but also reinforces deterrence as the essential buffer between competition and conflict.

Finally, the NSS contends that durable deterrence rests as much on economic and technological dominance as on military power. By preserving America’s lead in high-tech innovation, increasing its industrial capacity, ensuring energy dominance, and securing reliable access to critical minerals, the United States reduces adversaries’ incentives to challenge it militarily while incentivizing a realignment of countries toward U.S. interests. At the same time, the strategy underscores that economic strength alone is insufficient; it must be coupled with a military that is rigorously recruited, trained, equipped, and modernized to remain the world’s most lethal and technologically advanced deterrent force, protecting U.S. interests and preventing conflict.

The 2025 NSS is far from “business as usual.” It embraces sovereignty, fairness, and balance of power, asserting that peace rests on strength—not wishful thinking, unchecked interventionism, or self-imposed restraint. The strategy states that “in the long term, maintaining American economic and technological preeminence is the surest way to deter and prevent a large-scale military conflict,” thereby framing deterrence not simply as a matter of nuclear or conventional force posture, but as the cumulative product of industrial capacity, innovation, and sustained national investment. Within this logic lies a clear call to expand and emplace a robust, modern, flexible, and resilient nuclear arsenal capable of deterring nuclear attack, averting major war, and safeguarding America’s national interests.

Col. Curtis McGiffin (U.S. Air Force, Ret.) is Vice President for Education at the National Institute for Deterrence Studies and visiting professor at Missouri State University’s School of Defense and Strategic Studies. Views expressed in this article are his own.

The Case for Deterrence: What the 2025 NSS Gets Right was originally published on Global Security Review.