Extended deterrence, commonly known as the “nuclear umbrella,” represents America’s commitment to defend its allies against strategic threats, including the use of nuclear weapons. Since the late 1940s, this policy provides security guarantees to NATO members and Asian allies like Japan and South Korea.

Rising threats from adversaries like North Korea and Iran, coupled with the modernization of arsenals by Russia and China, underscore its continued necessity. Without this safeguard, allies may feel compelled to pursue independent nuclear programs, triggering preventable proliferation that can destabilize entire regions and weaken American influence.

Consider a scenario where the United States’ failure to build a peer theater nuclear capability and public statements are viewed by allies as a reduction in American nuclear commitments in East Asia. Japan, confronted by an assertive China and threatening North Korea, initiates a covert nuclear program, leveraging its advanced civilian nuclear technology and plutonium reserves. Constitutional constraints notwithstanding, mounting public anxiety could drive Tokyo toward its first nuclear test.

South Korea, facing similar security vulnerabilities, revives its previously dormant nuclear ambitions. Taiwan, under existential threat from China, sees nuclear capability as essential for survival. Alarmed by these developments, President Xi Jinping orders an accelerated attack on Taiwan and, potentially, attacks targets in South Korea and Japan to preempt support of Taiwan.

This ripple effect would yield devastating global repercussions. The Treaty on the Non-Proliferation of Nuclear Weapons (NPT), a cornerstone of nonproliferation, ceases in relevance. Nations such as Saudi Arabia, Turkey, Germany, and Poland might explore nuclear options. With more nuclear actors in play, risks increase as a statistical probability. Diplomatic and economic instability would likely surge, potentially fracturing alliances, crippling foreign investment, and destabilizing global markets.

Extended deterrence is not merely about preventing proliferation; it provides substantial military and economic benefits as well. American allies contribute robust defense capabilities, hosting critical strategic bases essential for American operations. South Korea’s military fought alongside American forces in every conflict since Vietnam, while Japan’s formidable naval and air capabilities enhance American strategic flexibility. European NATO allies provide indispensable missile defense and air operations infrastructure, reinforcing American global power projection.

Economically, the nuclear umbrella fosters stability, encouraging foreign direct investment from treaty allies like Japan, Germany, and South Korea—three of the top investors in the US. This security framework ensures mutual prosperity and deepens economic interdependence, strengthening not just trade partnerships but long-term strategic relationships. South Korea, the world’s 14th-largest economy, thrives under this arrangement, further reinforcing cross-border trade and investment.

Upholding extended deterrence demands a long-term investment of American resources, ensuring stability across NATO. Allied nations pledged to meet defense spending commitments, emphasizing the principle that collective security thrives on shared responsibility. Given that the US allocates just under three percent of its gross domestic product (GDP) to defense, committing at least two percent is a reasonable expectation.

Eleven nations met the two percent target in 2023, up from just four in 2017. President Trump’s pressure campaign on NATO defense spending is working. If every NATO nation adhered to the two percent minimum, the alliance’s total defense budget would rise by over $100 billion annually, reinforcing military capabilities, strengthening infrastructure, and fortifying global stability.

More than just a financial obligation, honoring these agreements is fundamental to sustaining NATO’s unity and trust. Increased investment not only bolsters collective security but also eases the strain on the US, which continues to shoulder the responsibility of protecting Western civilization from instability.

Extended deterrence long served as the backbone of global stability, shaping a world where security, military cooperation, economic prosperity, and nuclear nonproliferation are upheld. Stability is not self-sustaining; it demands vigilance, action, and unwavering commitment. NATO’s legacy proves this repeatedly. From coalition forces uniting in Kosovo to prevent ethnic cleansing, to NATO-led air campaigns in Libya that dismantled an oppressive regime, alliance members stood together in moments of crisis. Joint operations in Afghanistan, where NATO countries fought side by side for nearly two decades, showcased the strength of shared commitment. Even today, as NATO fortifies defenses in Eastern Europe, the principle remains unchanged. Security is only as strong as the unity behind it.

NATO’s Article 5 is more than a pledge; it is a promise that must be upheld through action. Security is not theoretical; it is built on resources, strategy, and cooperation. The deterrence piggy bank needs deposits, not just withdrawals. If allies fail to uphold their commitments, the burden on the US becomes untenable.

The stakes could not be higher. Geopolitical tensions are rising, nuclear threats are evolving, and adversaries are watching for cracks in the foundation. The American nuclear umbrella remains a pillar of international security, but it is only as strong as the resolve behind it. Allies must step up because if they do not, the rain will come, and they will find themselves unprotected in the storm.

Brandon Toliver, PhD, serves on the A4 staff of Headquarters Air Force. The views expressed are those of the author and do not reflect the official guidance or position of the United States government, the Department of Defense, the United States Air Force, or the United States Space Force.

The Nuclear Umbrella: Reassurance or Relic in a Shifting World? was originally published on Global Security Review.

ICBM EAR Report for 22 Feb 2025 was originally published on Global Security Review.

During the webinar, Lowther briefly touched on the alternative and numerically weaker concept of sizing America’s nuclear triad based upon “strategic sufficiency.” This approach would mean deploying just enough nuclear warheads to launch a counterforce first strike on the deployed nuclear delivery platforms of America’s adversaries. For example, it may be possible to strike eight nuclear-capable bombers, which carry 12 nuclear weapons each, with one intercontinental ballistic missile. Thus, the ratio, in this case, would be one American nuclear weapon for 96 (8×12) adversary nuclear weapons. One is strategically sufficient for 96.

Unfortunately, there are a number of challenges with strategic sufficiency as a concept. Let me explain.

It should first be noted that nuclear weapons do not exercise effective deterrence simply by their existence in the American inventory, nor merely by matching friendly weapons to enemy weapons on paper. American planners need to go much further.

The US needs to base its nuclear deterrent arsenal size, and its nuclear deterrent strategy and posture, on a realistic evaluation of possible scenarios. Adversaries will certainly perform such risk analysis. If America’s nuclear readiness falls short, in their minds, adversaries may seek openings to attack.

The American nuclear deterrent needs to include survivable, damage-limiting, and damage-equalizing second-strike capabilities, against both numerous enemy armed forces and extensive enemy countervailing (political control) assets. The US should also have the ability to restore intra-war deterrence and to have leverage during post-war armistice talks, a significant further number of warheads and delivery platforms deployed or in secure stockpiles.

Strategic Sufficiency

In the webinar, Lowther offers as an illustrative case where China’s new missile field deploys three hundred intercontinental ballistic missiles (ICBM), each with eight warheads. In this case, strategic sufficiency may require fifty ICBMs to hold the three hundred Chinese missiles at risk. Dynamic parity, in contrast, would dictate the US should field an arsenal closer in size to China’s, which in this limited example would be 300 missiles with a similar number of warheads.

Admittedly, strategic sufficiency is attractive for a country with a smaller arsenal, but it is also attractive to an adversary with a larger arsenal. The adversary may see strategic sufficiency as a strategy of weakness and built on a lack of will. The approach has a number of flawed assumptions.

First, strategic sufficiency assumes that all American nuclear weapons will succeed in striking their targets and destroying them. While American delivery systems are reliable, they have no experience under the harsh conditions of a nuclear conflict. Some weapons may malfunction, others will be destroyed in a first strike, weapons may not hit their target, and some will be destroyed by enemy defensive systems.

This is why targeteers often allocate two or more warheads to one enemy silo, for example, which is generally considered necessary for a successful counterforce strike. On this count alone, strategic sufficiency underestimates sizing requirements.

Second, a more serious flaw is the assumption that the United States can always launch a counterforce first strike. An adversary’s remaining weapons will still be in their silos, or in their hangars, when American warheads arrive. This is a foolish assumption. The US is unlikely to initiate a first strike, which means it must be able to absorb a strike and respond. Strategic sufficiency does not allow that.

Making the situation much worse is that China, North Korea, and Russia possess nuclear delivery platforms that are mobile, making them far harder to strike. Ballistic missile submarines at sea are, for now, hard to strike. Mobile ICBM launchers move positions constantly, and might also be camouflaged, for example, while inside shipping containers or railroad freight cars. Strategic bombers can maintain airborne alert. Other ICBM launchers can be hidden inside caves or tunnels until the moment they are ready to fire.

Third, the US is highly unlikely, as said above, to employ nuclear weapons in a first strike. A number of wargames played by the military and senior government leaders only underscores the cultural aversion to nuclear weapons use. This means the homeland is likely to face a nuclear attack before the president responds with whatever nuclear weapons remain. If the American arsenal is already smaller than the arsenals of adversaries, the US becomes an inviting target for a second strike or a strike from a different adversary.

Fourth, strategic sufficiency gives allies the impression that the United States has too few weapons to defend North America and both Europe and Asia. This belief may lead allies to seek their own arsenals.

As McGiffin and Lowther argue, dynamic parity is designed to address these specific challenges. China, North Korea, and Russia are very clearly looking to topple the American-led international system. Should the United States seek to build an arsenal that is too small to effectively deter the Authoritarian triad discussed here, not only will Americans suffer, but so will the free world. Moving from 5 percent of the defense budget to modernize the current arsenal to 8 to 10 percent of the defense budget to build the arsenal needed is not in the “too hard to do” category. It is time to recognize that strategic sufficiency is not sufficient.

Joe Buff is a Senior Fellow at the National Institute for Deterrence Studies.

Strategic Sufficiency Is Not Enough was originally published on Global Security Review.

The Role of First Use in Deterrence

American nuclear posture has long relied on an ambiguous first-use policy to enhance deterrence. Unlike a no-first-use policy, which commits a country to only retaliate in response to a nuclear attack. Ambiguity forces adversaries to consider the possibility that any aggression could provoke a devastating nuclear response, even in a non-nuclear conflict.

Today, the US faces a diverse array of threats from state and non-state actors, including revisionist powers like China and Russia, nuclear-armed rogue states like North Korea, and potential proliferators like Iran. The credibility of the American nuclear deterrent is critical in this environment. A first-use option deters conventional aggression from adversaries who may believe that their superior non-nuclear forces could overwhelm the US or its allies without triggering a nuclear response. If the US were to adopt a no-first-use policy, adversaries could be emboldened, believing they can engage in limited conflicts or conventional escalations without risking catastrophic consequences.

Credibility of Use

Nuclear deterrence rests not only on the existence of weapons but also on the belief that they will be used, if necessary. The credibility of the American nuclear deterrent, therefore, depends on a consistent and robust posture that leaves room for ambiguity. Even if morally troubling, this ambiguity serves to keep adversaries in check.

Credibility is essential in preventing both conventional and nuclear conflicts. The US must signal that it is willing to escalate when necessary, ensuring that adversaries believe they have no safe avenues to challenge American power. Both Moscow and Beijing are expanding their military capacities, with the Russian nuclear arsenal modernized and China rapidly growing its arsenal. Without the possibility of nuclear first use, these powers might test American resolve in regions like Eastern Europe, Taiwan, or the South China Sea, believing that Washington is reluctant to escalate.

This is where critics often misunderstand the moral and ethical dimensions of nuclear deterrence. A no-first-use policy may appear more humane, but by removing the strategic ambiguity that underpins deterrence, it risks emboldening adversaries to start conflicts that could spiral out of control. Paradoxically, maintaining a first-use option can be the best way to prevent nuclear war by ensuring adversaries never push the US into a corner where nuclear retaliation becomes necessary.

Continuity across Administrations

Regardless of who wins the November election, as Matthew Costlow noted, continuity in nuclear policy is essential for maintaining credibility. The US has had a bipartisan consensus on maintaining nuclear deterrence since the dawn of the atomic age. Both Republican and Democrat administrations preserved the first-use option because they recognize the value of strategic ambiguity in deterring aggression.

A Trump administration might be inclined to preserve a muscular nuclear posture to project strength, while a Harris administration might come under pressure from progressives to move towards a no-first-use policy—aligning with global disarmament movements. However, any shift towards no first use would erode the credibility of US commitments to allies in Europe, Asia, and the Middle East. The North Atlantic Treaty Organization (NATO), in particular, relies on the American nuclear umbrella, and a no-first-use policy could cause allies to question Washington’s willingness to respond to conventional or nuclear threats. Such a policy could cause a cascading effecting of nuclear proliferation amongst our allies and adversaries.

Moreover, a shift in policy during an administration change could create instability by signaling to adversaries that US nuclear posture is fluid and negotiable, making deterrence less effective. Credibility in nuclear deterrence is not just about weapons but also about long-term consistency and resolve, which are crucial in managing the expectations of allies and adversaries alike.

Moral and Ethical Considerations

The moral and ethical dilemmas posed by nuclear weapons are undeniable. The catastrophic humanitarian consequences of nuclear use make it tempting to adopt a policy that seeks to limit the circumstances under which such weapons might be employed. But the ethics of deterrence also hinge on preventing war in the first place. If the fear of nuclear first use keeps adversaries from initiating conflicts that could escalate into full-scale war, then the policy serves a larger ethical purpose: preserving peace.

In the real world of international politics, where states act for self-interest and survival, moral purity often clashes with pragmatic necessities. Nuclear deterrence, including the first-use option, is a grim but necessary strategy for ensuring peace and stability in a world still defined by competition among great powers.

Conclusion

As the 2024 election approaches, the future of American nuclear policy should be beyond partisan politics. The US must maintain its nuclear first-use policy regardless of which administration takes office, whether led by Donald Trump or Kamala Harris. The strategic logic of deterrence, the credibility of use, and the need to prevent adversary aggression all argue for preserving this policy. While the moral and ethical concerns surrounding nuclear weapons are valid, the preservation of peace and the deterrence of large-scale conflicts depend on maintaining the ambiguity that has underpinned nuclear strategy for decades. A stable and secure world requires that the US continue to hold the line on its nuclear posture—now and in the future.

Aaron Holland is a PhD candidate at the University of Utah and an analyst at the National Institute for Deterrence Studies.

Maintaining America’s First-Use Policy was originally published on Global Security Review.