Few scenarios scare pundits and policymakers as much as the prospect of nuclear proliferation. Russia’s willingness to dangle the threat of deploying tactical nuclear weapons in its war against Ukraine, U.S. President Donald Trump’s ambiguous interest in nuclear testing, and the imminent expiration of the 2010 New START treaty (which limits the size of Russian and U.S. nuclear arsenals) have reminded the world of the abiding destructive potential of nuclear weapons and reanimated fears of their use. American leaders are convinced that the spread of nuclear weapons would deeply hurt U.S. strategic interests and further destabilize the already fragile global order. In recent months, they have doubled down on their commitment to preventing proliferation, and the June strikes against nuclear sites in Iran have shown that Washington will use force to prevent more countries from acquiring the bomb.
For decades, the United States invested in a nuclear order built around nonproliferation, even as Cold War disarmament agreements such as the Anti-Ballistic Missile Treaty expired. Opposing proliferation among unreliable states and adversaries makes sense, but a blanket opposition to the further spread of nuclear weapons obscures the significant benefits they can bestow. The United States would do well to reconsider its strict adherence to nonproliferation and encourage a small set of allies—namely Canada, Germany, and Japan—to go nuclear. For Washington, selective nuclear proliferation would allow these partners to take on larger roles in regional defense and decrease their military dependence on the United States. For these allies, in turn, acquiring nuclear weapons provides the most dependable protection against the threats of regional foes, such as China and Russia, as well as a United States less committed to its traditional alliances.
Skeptics and nuclear pessimists might blanch at the idea of a world with more nuclear-armed powers, but such concerns are less warranted when proliferation is pursued selectively. Canada, Germany, and Japan have proven track records of rational policymaking and domestic stability that will make both nuclear accidents and any spiral of uncontrolled escalation unlikely. And, if carefully managed, there is ample reason to believe that proliferation in these countries would not lead to widespread efforts by others to develop their own bombs.
Far from ushering in a frightening new era of global instability, selective proliferation would help uphold the post–World War II order. Were Canada, Germany, and Japan to acquire nuclear weapons, they would rebalance global military capabilities in favor of a coalition of states committed to the rules-based system and to stopping the erosion of its key norms, especially territorial integrity. Selective proliferation would thus revitalize the increasingly brittle post-1945 order that has so benefited the United States and its allies.
A WIN-WIN
Senior U.S. officials have repeatedly emphasized the need to shift the burden of continental defense onto European allies and decrease their military dependence on the United States. Confronted by the geopolitical challenge of a rising China in East Asia and pressed for resources to address issues at home, Washington has come to see ending European free-riding as a top strategic priority. What stands in the way of Europe’s ability to provide for its own security today—and thus blocks a significant U.S. retrenchment—is the lack of German nuclear forces. Throughout the Cold War, U.S. leaders had hoped to withdraw American forces from Europe but determined that unless Germany acquired a nuclear deterrent, the continent would not be able to guarantee its own security. As the historian Marc Trachtenberg has noted, the United States rightly judged that British and French nuclear forces “could not provide the necessary degree of reassurance” that Europe would be able to deter the Soviet Union and its vast nuclear arsenal. Today, the same roadblock remains. Encouraging Germany to develop its own nuclear weapons would finally create the kind of self-sufficient Europe that enables an American exit.
German leaders and the German public recognize that military dependence on the United States leaves their country vulnerable to Washington’s whims. Shortly after his election in February 2025, Chancellor Friedrich Merz announced that it was time to “achieve independence” from the United States, and he has since become an outspoken proponent of substantial rearmament. But it will take a long time to build up Germany’s conventional capabilities, and Berlin still lacks a clear vision for how to meet the ambitious defense spending target of five percent of GDP that Merz and other European leaders agreed to at a NATO summit in June. Germany’s ongoing commitments to provide war materiel to Ukraine and the population’s reluctance to undertake military service hinder a speedy conventional military buildup. The development of an independent nuclear force would safeguard Germany against the possibility of a sudden U.S. withdrawal from Europe while offering a feasible and meaningful way to fulfill the five percent pledge.
Japanese proliferation will go a long way toward achieving the United States’ main goal in East Asia, namely, the containment of China through strong local alliances. From Washington’s perspective, the primary threat posed by Beijing is that it might achieve regional dominance and develop the military potential to seriously threaten the United States and its interests by, for example, disrupting semiconductor supply chains or establishing forward bases beyond its territory in East Asia and even further afield. Such Chinese regional hegemony would pose a major challenge to the United States.
Japan already enjoys the defensive benefit of being an archipelago country separated from its adversaries by the sea. If combined with independent nuclear capabilities, that advantage would effectively guarantee Japan’s security in the face of outside threats—and ensure that it does not fall under Chinese control. Beyond better defending itself, a nuclear-armed Japan would provide a more credible and immediate form of extended deterrence to East Asia than the United States can provide. China might doubt Washington’s willingness to risk nuclear war over developments in East Asia, but Japan’s proximity and direct stake in regional stability render its commitments far more credible.
More nuclear weapons might indeed be better.
A nuclear-armed Japan would also insert an extra layer in crisis escalation scenarios, allowing an effective response to Chinese aggression without directly drawing in the United States. When contemplating an attack on Japan, China would be forced to consider the monumental costs of Japanese retaliation independent of any additional American support. Having nuclear weapons would also equip Japan, and perhaps East Asia more broadly, to handle a sudden change in Washington’s security commitment. The Trump administration’s newest National Defense Strategy prioritizes the defense of the U.S. homeland and the Western Hemisphere over the threats emanating from China and Russia, signaling a potentially seismic shift in orientation.
In North America, Canadian proliferation would enhance American homeland security. Given the integration of the Canadian and American militaries within NATO and the bilateral air defense system NORAD, the two countries would be fighting together in virtually any conceivable hemispheric defense scenario. Although Canada does not face immediate threats to its territorial integrity from Russia or China, its relations with both countries have deteriorated significantly over the past decade. A Canadian nuclear deterrent reduces the chance that the United States would be called on to defend its continental neighbor, effectively freeing up American capabilities and removing an avenue of potential geopolitical encroachment. American support for a Canadian nuclear deterrent would also provide crucial reassurance about Washington’s commitment to continental defense at a time when the neighbors’ bilateral relationship is under strain.
For Canada in turn, possessing nuclear weapons signals to the United States that it, too, accepts shared responsibility for continental defense and that Ottawa can deter potential aggressors without American support. As Canadian Prime Minister Mark Carney put it in March, Canada’s “old relationship” with the United States is “over.” Going nuclear would prepare Ottawa to face this new world by reconfiguring the continental partnership and helping the country go it alone. Further, the challenges of meeting NATO’s five percent spending target are arguably more significant for Canada than they are for Germany. A modest nuclear deterrent offers a solution to this challenge that also results in a meaningful strategic asset in Canada’s arsenal.
Canada, Germany, and Japan each possesses the scientific and industrial capacity to successfully develop nuclear weapons on its own. For instance, Canada’s role as a major supplier of fissile material provides the basis for a joint effort to make these new nuclear capabilities a reality. What the three allies would need—and what the United States can and should provide—is public support and diplomatic cover for their transition to becoming nuclear-armed states, as well as technical and doctrinal guidance to ensure robust command and control safeguards.
NUCLEAR FIX
Traditionally, nuclear proliferation has been understood as a risk to the stability of the international order. As states acquire nuclear capabilities, regional and global balances of power shift, calling into question existing security arrangements. A state with a nuclear deterrent, the thinking goes, can behave predatorily since it is now insulated from attempts to rein it in. This conventional view is wrong—or at the very least too simplistic—as it assumes all proliferators will behave the same way. When states committed to defending international rules and norms acquire nuclear capabilities, proliferation, in fact, increases the stability and strength of the global order.
Canada, Germany, and Japan are among the leading states committed to the rules-based international order. All three frame their foreign policies and even their state identities in terms of good international citizenship. Select nuclear proliferation in these states would rebalance military capabilities and create a unified coalition of nuclear powers committed to thwarting potential revisionists. Such a coalition would help prevent further erosion of the rules, norms, and institutions of the post-1945 order, including the norm against conquest. In addition to the material sources of stability it would provide, selective proliferation would thus strengthen the normative sources of stability essential to international order.
Selective nuclear proliferation should thus be framed and understood as an investment in the revitalization of that order. Effectively, Canada, Germany, and Japan would be helping to fill the gaps that have led Russia to see more favorable conditions for revisionism and that could lead China to make a similar calculation.
BE NOT AFRAID
Many of the typical concerns raised by opponents of nuclear proliferation do not apply to selective proliferation by U.S. allies. For instance, there is no reason to fear that Canadian, German, or Japanese nuclear weapons would end up in the hands of rogue states or terrorist organizations; all three are paragons of responsibility, state capacity, and domestic stability. There is also no need to worry about the rationality of these states. If North Korean leader Kim Jong Un can exercise prudence and caution with regard to his nuclear arsenal, leaders in Ottawa, Berlin, and Tokyo can reasonably be expected to do the same.
Another concern is that if a few states pursue nuclear capabilities, a plethora of others will then move to do the same. This argument is unconvincing. Knock-on proliferation is typically the result of preexisting rivalries and heavily conditioned by geographic contiguity, as exemplified by Pakistan’s pursuit of a bomb in response to Indian proliferation. Canadian proliferation is unlikely to spur, say, Mexico, to pursue its own bomb. The European states that would have the greatest incentive to counter German proliferation—the United Kingdom and France—already have their own nuclear forces. Other possible proliferators, such as Poland, might be convinced to forgo an independent nuclear weapons program with multi- or bilateral nuclear sharing agreements. In East Asia, an acquisition of nuclear weapons by Japan might push South Korea to act on its long-held nuclear ambitions, but Seoul’s integration into the American security architecture substantially reduces its incentives to do so. Japan’s geographic advantage and the fact that it is not stuck in a frozen conflict (as South Korea is with a nuclear-armed North Korea) make it a more attractive candidate for selective proliferation than South Korea. To be sure, if Seoul decided to forge ahead and build a bomb, it would also be a safe and reliable nuclear custodian. Although Taiwan might theoretically want to follow suit, it has no plausible pathway to act upon this desire because of its precarious geopolitical position in regard to China.
The potential for accidents involving nuclear weapons remains a reasonable concern. Although it is true that the spread of nuclear weapons would technically increase the possibility of inadvertent nuclear war, the risk remains so small that it would likely be outweighed by the tangible benefits to international stability and security. Even during the height of the Cold War, a time fraught with immense strategic and ideological rivalry, the two superpowers successfully avoided a nuclear exchange. One of the virtues of selective nuclear proliferation is that Canada, Germany, and Japan are among the most well-equipped to minimize additional risk. All have highly professional militaries, robust civilian control of those armed forces, and foreign ministries highly skilled in peaceful conflict resolution.
Other objections do not withstand scrutiny. For example, some U.S. experts have opposed proliferation among American allies on the ground that it would undermine the United States’ influence, specifically over Germany and Japan. The claim conflates strategic instruments with objectives. Washington’s fundamental aim in Europe and East Asia is to prevent any single state from dominating either region. Although American influence over allies offers an indirect and uncertain path to preventing the rise of a regional hegemon, nuclear weapons in Germany and Japan would virtually guarantee that result. In other words, selective proliferation sacrifices some U.S. influence, but only in exchange for the objective it was designed to achieve in the first place.
The most understandable hurdle—and potentially the most difficult to overcome—is public opposition to proliferation. Japan’s experience of the atomic bombings of Hiroshima and Nagasaki remains central to its collective memory. Post-1945 pacifism and general skepticism about nuclear energy predispose many Germans to oppose an independent deterrent. And Canada has long resisted even hosting nuclear weapons on its territory, let alone acquiring its own. Overcoming this apprehension will no doubt be difficult, and states will have to convince skeptical citizens that the acquisition of nuclear weapons will not just keep them safer but also boost the overall health of the rules-based order.
PROCEED WITH CAUTION
Implementing selective proliferation will not be easy or without risk. An immediate practical consideration is that Canada, Germany, and Japan would each need to withdraw from the Nuclear Nonproliferation Treaty, in which they agreed not to develop a nuclear bomb. Commitment to the proper process for withdrawing from the treaty under international law would signal their intent to stabilize the international order and strengthen international security rather than weaken both. To the extent possible, NPT withdrawals should be carefully broached to key allies in advance to minimize alarm. Although it is unrealistic to expect all other countries to accept such withdrawals, pursuing nuclear proliferation in a responsible and transparent way would signal each country’s good intentions. It is here that American diplomatic cover can prove particularly valuable, coordinating with France and the United Kingdom to ensure that the new nuclear states do not become the target of United Nations Security Council enforcement measures.
To provide as much reassurance to skeptical states as possible, the three proliferators should consider adopting a “no first use” policy, at least while they remain under the American nuclear umbrella. While NATO was unwilling to commit to such a policy during the Cold War, Canada, Germany, and Japan face less stringent security challenges, at least at present, and can therefore contemplate taking this step in order to signal their commitment to maintaining the status quo.
Selective nuclear proliferation requires careful management to fulfill its potential, but it offers genuine ground for optimism. The case for it remains as controversial as ever, but it does matter greatly which countries get the bomb. If the proliferators are allied, stable governments and responsible members of the international community, then more nuclear weapons might indeed be better.
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