NATO’s recent establishment of Baltic Sentry (2025), Eastern Sentry (2025), and Arctic Sentry (2026) reflects more than a response to Russian aggression. Collectively, these operations demonstrate how modern deterrence has evolved to address persistent airspace violations, hybrid warfare, cyber-attacks, sabotage of critical infrastructure, and grey-zone coercion. While these missions are conventional military operations, they derive their strategic credibility from something far more significant, NATO’s integrated nuclear deterrence architecture.

This distinction is critical. NATO’s Sentry operations are not isolated military activities; they are conducted within an alliance whose conventional forces are underwritten by the collective nuclear capabilities of the United States, the United Kingdom, and France. Any adversary contemplating escalation understands that conventional confrontation with NATO carries the inherent risk of nuclear escalation. This integration between conventional and nuclear deterrence has underpinned Euro-Atlantic security for more than seventy years.

For the Indo-Pacific, the lesson is clear. As China rapidly expands its nuclear arsenal, North Korea continues to develop increasingly sophisticated nuclear and missile capabilities, and Russia under Vladimir Putin has revived Cold War-era nuclear coercion, regional allies cannot assume that conventional military cooperation alone will provide credible deterrence. If deterrence is to succeed, it must be built upon a coherent nuclear alliance before a crisis emerges, not after deterrence has already failed.

Conventional Operations Backed by Nuclear Deterrence

The strategic significance of NATO’s Sentry operations lies not simply in what they do, but in what stands behind them. Baltic Sentry enhances surveillance and protection of undersea communications cables, energy infrastructure, and maritime approaches following repeated acts of sabotage and suspicious activity in the Baltic Sea. Eastern Sentry reinforces NATO’s eastern flank through enhanced air policing, intelligence sharing, and rapid response capabilities in the face of persistent Russian military activity. Arctic Sentry reflects NATO’s growing focus on the High North as Russia and China expand their military presence in an increasingly contested region.

These operations improve situational awareness, interoperability, and alliance readiness. Yet none of them exist in isolation. Their credibility stems from NATO’s integrated command structure, collective defense commitments under Article 5 of the North Atlantic Treaty, shared military planning, and, fundamentally, the Alliance’s nuclear deterrence posture. NATO’s Nuclear Planning Group, alongside the independent nuclear forces of the United Kingdom and France and the United States extended nuclear deterrence commitments, ensures that any conventional confrontation carries strategic consequences far beyond the immediate theater.

This layered approach to deterrence is central to NATO’s success. Conventional operations deter day-to-day coercion, while nuclear deterrence prevents adversaries from believing they can escalate a conventional conflict without unacceptable consequences. The two cannot be separated; together they create a coherent deterrence architecture.

The Indo-Pacific’s Strategic Environment Has Changed

The Indo-Pacific now faces a security environment increasingly defined by nuclear competition. China’s rapid expansion and modernization of its nuclear arsenal is reshaping the regional balance of power. At the same time, Beijing continues to employ sustained grey-zone coercion through military pressure around Taiwan, coercive operations in the South China Sea, cyber campaigns, and increasingly frequent air and maritime incursions directed at neighboring states.

North Korea’s advancing nuclear weapons and ballistic missile programs add another layer of strategic complexity. Pyongyang’s continued weapons development increases the likelihood that any regional crisis could involve nuclear coercion or escalation.

Meanwhile, Russia’s full-scale invasion of Ukraine has demonstrated that nuclear weapons remain central to great-power competition. Throughout the conflict, President Vladimir Putin has repeatedly employed nuclear rhetoric and strategic signaling to deter Western intervention. The assumption that the end of the Cold War marked the end of nuclear coercion has proven false.

For Indo-Pacific allies, this means they are confronting not one, but three nuclear-armed challengers whose strategic interests increasingly overlap. Yet the region’s security architecture remains fragmented.

The Missing Foundation

The United States maintains strong bilateral alliances with Australia, Japan, South Korea, and the Philippines. Regional initiatives such as AUKUS and the Quad have strengthened defense cooperation, technological collaboration, and strategic coordination. These arrangements make important contributions to regional security.

However, they do not constitute an integrated alliance comparable to NATO. They lack common command arrangements, formalized collective defense obligations across the region, institutionalized nuclear consultation mechanisms, and a unified framework for integrating conventional and nuclear deterrence. This matters because conventional military cooperation alone cannot provide fully credible deterrence against nuclear-armed adversaries. NATO’s experience demonstrates that conventional operations derive their strategic weight from the knowledge that they are backed by a credible and integrated nuclear alliance. Without that strategic foundation, conventional activities risk being viewed as isolated demonstrations of resolve rather than components of a comprehensive deterrence posture. The Indo-Pacific is therefore attempting to strengthen conventional deterrence without first establishing the alliance architecture that gives such deterrence its greatest credibility.

Building Deterrence Before Crisis

History consistently demonstrates that alliances formed during conflict rarely prevent that conflict. They manage its consequences instead. Europe’s recent experience illustrates this lesson. Many of NATO’s most significant reforms, including enhanced forward deployments,

strengthened infrastructure protection, expanded readiness, and the establishment of the Sentry operations, were accelerated in response to deteriorating security conditions following Russia’s aggression against Ukraine. They represent adaptation after strategic warning signs became impossible to ignore.

The Indo-Pacific still has an opportunity to act before reaching a comparable point. Rather than waiting for a crisis over Taiwan, the South China Sea, or the Korean Peninsula to force hurried institutional change, regional democracies should begin developing the alliance structures necessary to sustain credible deterrence.

Such an alliance would not require every member to possess nuclear weapons. Instead, it would integrate conventional planning with extended nuclear deterrence, establish mechanisms for strategic consultation, coordinate contingency planning, strengthen interoperability, and ensure that regional conventional operations are supported by a credible nuclear deterrent capable of deterring nuclear-armed adversaries.

Conclusion

NATO’s Baltic Sentry, Eastern Sentry, and Arctic Sentry operations are not simply conventional military initiatives. They are visible expressions of a much deeper strategic reality: conventional deterrence is most credible when backed by an integrated nuclear alliance. Their effectiveness rests not only on ships, aircraft, and surveillance systems, but on the certainty that any attempt to escalate against NATO would confront the Alliance’s collective nuclear deterrent.

The Indo-Pacific faces an increasingly dangerous strategic environment characterized by a rapidly expanding Chinese nuclear arsenal, an emboldened North Korea, and a resurgent Russia that has returned nuclear coercion to the center of international politics. In such an environment, conventional cooperation alone is unlikely to provide sufficient deterrence.

The central lesson from NATO’s Sentry operations is therefore not that the Indo-Pacific should simply replicate these missions. It is that such operations derive their credibility from the nuclear alliance that stands behind them. Waiting to build that alliance until deterrence has failed would repeat the strategic mistakes history has repeatedly exposed. The time to establish an integrated Indo-Pacific nuclear alliance is before a crisis begins, not after conflict has already become unavoidable.

Natalie Treloar is the Australian Company Director of Alpha-India Consultancy, a Senior Fellow at the Indo-Pacific Studies Center (IPSC), a Fellow at the National Institute for Deterrence Studies (NIDS), and a member of the Open Nuclear Network (ONN). Views expressed in this article are the author’s own.

NATO’s Sentry Operations Show Why the Indo-Pacific Needs a Nuclear Alliance was originally published on Global Security Review.

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.

The primary objective of Biden’s integrated deterrence strategy was to harmonize and unify the efforts of various government agencies and allied nations to deter aggression from China and other hostile actors. To achieve this objective, the strategy aimed to maximise the utilisation of all available tools of American power, encompassing diplomacy, intelligence, economic assistance, and force posture decisions. Integration with allies and partners was an integral component of Biden’s deterrence strategy and would be achieved by enhancing the interoperability of allied military forces and coordinating the diplomatic and economic initiatives of friendly nations.

While the goals of integrated deterrence appear sensible, many expressed concerns about the concept. Some claimed the term was not new or unique. It simply described the implementation of any effective, tailored deterrence strategy that leverage various organisations to prevent hostile actions.

American deterrence was executed in an integrated fashion throughout the Cold War by necessity, thanks to the size and significance of the Soviet threat. Concerns were also expressed that proponents of integrated deterrence overstated the ability of sanctions, diplomacy, and other non-military tools to prevent conflict. History shows that the threat of major military action has a unique strength in deterring an enemy, especially when that threat comes from a nation with a nuclear arsenal.

Regardless of one’s stance on integrated deterrence and its implementation, a coordinated US strategy that leverages the strengths of its allies should be preferred to the alternative currently being pursued in Washington. A lack of integration in deterrence matters is evident both within the US government and in its interactions with partners and allies.

Within the United States government, there are several reported disconnects between President Trump and senior members of his administration. For example, Secretary of State Marco Rubio was first informed of Trump’s proposal to take Gaza by military force and evict Palestinians while watching a press conference held by Trump and Israeli Prime Minister Benjamin Netanyahu. Furthermore, it was recently reported that Rubio is “privately frustrated that Trump has effectively sidelined him.” More recently, Signal messages disclosed highlight significant differences between Vice President Vance and President Trump on the timing and signaling associated with strikes on Houthi targets.

This lack of vertical integration diminishes the authority that the secretary holds in meetings with both allies and adversaries. Additionally, it eliminates the potential for any exchange of ideas that could transpire within the Department of State to develop more effective policy options to present to the president.

Horizontal integration of deterrence across various departments was also weakened, partially by budgetary cuts and eliminations of entire organizations. Foreign assistance and development resources were pivotal components of the 2022 Indo-Pacific Strategy. However, extensive cuts made to the United States Agency for International Development and other government agencies by the Department of Government Efficiency did not fully consider or comprehend the regional implications or potential negative impacts on deterrence.

To date, much of Trump’s foreign policy is focused on addressing conflicts in Europe and the Middle East. A strategy for dealing with China, beyond the use of tariffs and other economic measures, is yet to be revealed. There are lessons to be learned from what has transpired with allies facing a menacing Russian threat in Europe.

President Trump consistently urges the North Atlantic Treaty Organization’s (NATO) member-states to significantly enhance their defence expenditures, even suggesting that 5 percent of their gross domestic product (GDP) may be an appropriate threshold. For those nations that fail to meet NATO’s spending guidelines, Trump stated that US military support under Article 5 may not be available. While NATO nations were increasing defense spending prior to Trump taking office (a 20 percent increase in 2024), Germany and the United Kingdom (UK) recently announced plans to further bolster defense budgets.

While additional insights into Trump’s approach to allies in the Indo-Pacific are anticipated in the coming weeks and months, Australia should draw upon several valuable early lessons. The first pertains to the long-standing Canberra tradition of analyzing and dissecting the statements and writings of senior officials within an American administration to comprehend policy. Maintaining cordial relations with officials at all levels of the US government remains prudent, but it is uncertain whether statements from senior administration officials can be relied upon to fully reflect Trump’s perspectives.

Furthermore, the current level of Australian defense spending, which accounts for 2 percent of GDP, will not meet Trump’s expectations for allies. A pre-emptive move to increase defense spending to 2.5 percent of GDP by 2027, similar to what was announced in February by the UK, would demonstrate Australia’s national commitment to addressing its deteriorating strategic circumstances and to contributing more towards its share of the alliance. If President Trump has made one thing clear to allies, it is that if they do not value their own defense neither will he.

Carl Rhodes is founder of Robust Policy and a senior fellow with the National Institute for Deterrence Studies. Carl hosts the Deterrence Down Under podcast and previously spent 25 years with RAND Corporation. Carl has a PhD in chemical engineering from Caltech.

Trump’s Disintegrated Deterrence and Lessons for Australia was originally published on Global Security Review.