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.

A Network of Powerful Allies

One of the strongest indicators of America’s continued leadership is its robust network of alliances. Over 50 nations are directly allied with the US, forming a global coalition that includes some of the world’s most powerful economies. Countries like Japan, the United Kingdom, France, and Australia consistently align themselves with American leadership, not just in military terms but also economically and diplomatically. Even in regions like the Middle East, traditional allies such as Saudi Arabia and emerging partnerships are fortifying the US’s global standing.

Contrast this with the coalition of China, Russia, North Korea, and Iran. While this quartet may represent a serious challenge, it pales in comparison to the extensive alliances that the US leads. Most crucially, while Russia and China may appear aligned in the short term, they are not close allies in any deep or historical sense. The two powers have a long and fraught history, marked by strategic rivalry and suspicion. Their partnership today is one of convenience rather than genuine alignment. In the end, history tells us that such partnerships are prone to fracture, especially when national interests clash.

The reality of America’s network of allies compared to the alliance of China, Russia, North Korea, and Iran is stark. This balancing coalition does not even come close to the strength of the band wagoning coalition the US possesses. For instance, the North Atlantic Treaty Organization (NATO), with its 31 member states, represents not only the most powerful military alliance in history but also an economic powerhouse, accounting for over 30 percent of global gross domestic product (GDP).

In contrast, China and Russia are economic competitors more than collaborators, and their combined GDP does not come close to rivaling the economic output of the US and its allies. Furthermore, China’s partnerships with nations like Iran and North Korea are limited by geography, sanctions, and divergent interests. North Korea is a heavily sanctioned and isolated state with little economic or strategic leverage beyond its nuclear capabilities, while Iran is mired in regional conflicts that prevent it from playing a major global role.

In essence, while China, Russia, North Korea, and Iran may occasionally coordinate to challenge the West, their relationships lack the cohesion, shared values, and the long-term strategic alignment of the American-led alliance system. This coalition cannot hope to rival the strength, stability, and global reach of America’s network of alliances. For all the talk of a multipolar world, the US remains at the center of the most powerful and united coalition of nations in modern history, a fact that ensures its continued dominance on the global stage.

The Strategic Advantage of Geography

Another underappreciated advantage is geography. The United States enjoys a position of unmatched security, largely thanks to what scholars like John Mearsheimer call the “stopping power of water.” Unlike any other global power, the United States benefits from being bordered by two vast oceans. These natural barriers serve as formidable buffers against potential adversaries, significantly reducing the likelihood of direct invasion or immediate military threats to the mainland.

This geographic advantage has profound implications for national security and global influence. Unlike Russia, which shares extensive borders with Europe and Central Asia, and China, which borders several regional rivals including India, Japan, and Vietnam, the US is largely insulated from the chaos of regional disputes.

Moreover, this geographic separation means that the US can maintain a relatively smaller standing army compared to continental powers—focusing instead on advanced naval and air forces capable of projecting power far from its shores. American military bases, fleets, and alliances stretch across the world, but the mainland remains safely beyond the reach of conventional military threats.

This position gives the US a level of strategic flexibility that few nations can match. That is not to say the US Navy does not have issues facing its future, especially with shipyards and defense procurement. However, it is still considered the greatest Navy in the world as of 2024.

The Monroe Doctrine

Part of what makes the US so unique is its role as the uncontested regional hegemon in the Western Hemisphere. The Monroe Doctrine has long established the principle that no foreign power should interfere in the affairs of the Americas, solidifying U.S. dominance in its own region. No other nation on Earth holds this level of regional control.

This unrivaled regional hegemony allows the US to focus on maintaining global stability and leading from a position of strength. As long as the Western Hemisphere remains secure, the US can project power abroad with confidence, knowing that its backyard is free from external threats.

The Interconnected Economies of the U.S. and China

Finally, the specter of the so-called Thucydides Trap—the idea that a rising power (China) will inevitably clash with an established one (the US)—is not as likely as it may seem. While it is true that China’s economic and military rise is a concern, the interconnectedness of the two economies makes a full-blown conflict far less probable. The US and China are not just rivals; they are deeply intertwined economically. From trade to investment to the global supply chain, the economic fates of both nations are linked in ways that make large-scale conflict costly for either side.

This economic entanglement offers a powerful deterrent against conflict. Both nations have a vested interest in maintaining peace and stability, knowing that any war would be mutually destructive. This interdependence, in many ways, acts as a stabilizing force, reducing the likelihood that the US and China will fall into the trap of inevitable conflict. However, it is worth noting that much of the same was said about the European powers just before World War I.

Conclusion: A Future of Optimism, Not Decline

Despite the challenges posed by emerging powers and the uncertainties of the global political landscape, the US remains in a position of unparalleled strength. Its vast network of powerful allies, its strategic geographic advantage, the stability of the Monroe Doctrine, and the economic interdependence with China all suggest that the US’s role as the world’s leading hegemon is secure for the foreseeable future.

Rather than succumbing to the doom and gloom of some political pundits, it is time to recognize the many reasons for optimism. The US has the tools, alliances, and strategic advantages to maintain its leadership and continue shaping a peaceful, prosperous global order.

Aaron Holland is a PhD candidate at the University of Utah and an Analyst at the National Institute for Deterrence Studies. All views expressed here are the author’s own.

The Resilient Hegemon: Why America’s Global Leadership Endures was originally published on Global Security Review.