Late last year, the administration of Donald Trump released the National Security Strategy 2025, a document that carries a distinctly manifesto-like character. It reaffirms the maintenance of overwhelming U.S. military power and nuclear deterrence, prioritizes next-generation missile defense under the Golden Dome initiative and places the defense of Taiwan at the top of U.S. security objectives.

Most notably, the strategy elevates the “stability of the Western Hemisphere” and the exclusion of hostile powers as its foremost regional priorities, explicitly signaling Washington’s intent to block China’s expanding presence in Latin America.

In Asia, while the U.S. reiterates its commitment to Taiwan’s defense, the NSS also suggests a recalibration of U.S.-China relations — from “strategic competition” toward a more narrowly defined “economic competition” — implying a search for greater stability in the bilateral relationship.

This strategic direction was further clarified in Secretary of Defense Pete Hegseth’s Dec. 6 speech at the Reagan National Defense Forum (RNDF). Hegseth articulated a vision that seeks to combine strengthened deterrence against China with strategic stability, explicitly invoking the logic of Cold War-era U.S. policy toward the Soviet Union. His remarks echoed a fusion of the Reagan administration’s early emphasis on strategic defense and nuclear superiority with its later embrace of arms control.

On nuclear deterrence, Hegseth underscored the modernization of the nuclear triad — intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles (SLBMs) and strategic bombers — alongside the development of “additional options for deterrence and escalation management.” He declared unequivocally that “even in a world with two major nuclear peers, the United States will not allow itself to be vulnerable to nuclear coercion.”

At present, however, the Trump administration has yet to release a Nuclear Posture Review, leaving key aspects of its nuclear strategy opaque. Meanwhile, within U.S. strategic circles, China’s rapid nuclear buildup has triggered renewed debate over whether Washington should accept a framework of nuclear parity with Beijing as the basis for strategic stability. This debate is inseparable from the challenge of confronting the two nuclear peer competitors — China and Russia — simultaneously, a condition often described as the “two-peer nuclear problem.”

The strategic blueprint laid out in the Trump administration’s 2026 National Defense Strategy, while not the focus of this article, strengthens, rather than contradicts, my analysis. At any rate, NSS 2025 and Secretary Hegseth’s RNDF speech, both early signals of the second Trump administration’s strategic direction, have largely been corroborated by NDS 2026. For the purposes of this article, however, my intention is to examine the strategic meaning of the Trump administration’s “Western Hemisphere first” posture and explore, hypothetically, how Japan might leverage this shift in rethinking alliance-based deterrence.

China has in recent years accelerated both the quantitative and qualitative expansion of its nuclear forces. Estimates suggest that Beijing may possess more than 1,000 nuclear warheads by 2030. This buildup includes new ICBMs, SLBMs, air-launched ballistic missiles (ALBMs), large-scale construction of underground missile silos and the deployment of low-yield nuclear warheads and dual-capable missile systems.

A central driver of this expansion is China’s desire to deter U.S. military intervention in a Taiwan contingency. Increasingly, analysts argue that Beijing is moving away from its long-standing doctrine of “minimum deterrence” and toward a posture that allows for nuclear coercion and even limited first-use options.

As U.S.-China nuclear parity approaches, the likelihood of large-scale nuclear war may diminish, but the risk of limited conventional conflict rises — a phenomenon known as the “stability-instability paradox.” During the Cold War, U.S.-Soviet nuclear balance coincided with Washington’s inability to prevent Soviet conventional interventions on its periphery. A similar dynamic could lead China to believe it can undertake military action against Taiwan while deterring U.S. escalation.

U.S. nuclear architecture was designed for a world dominated by a single nuclear peer — the Soviet Union, and later Russia. The emergence of a China-Russia “two-peer” nuclear environment demands a fundamental rethinking of deterrence, extended deterrence credibility, crisis stability and the feasibility of arms control.

Current U.S. debates fall broadly into two camps. One argues for the pursuit of nuclear superiority, advocating expanded arsenals and more flexible nuclear options to deter adversary adventurism through dominance. The other prioritizes strategic stability under conditions of parity, emphasizing transparency, crisis communication and limited arms control to prevent miscalculation.

Neither approach alone is sufficient. A drive for superiority risks spiraling costs and reciprocal buildup, while an uncritical acceptance of parity risks repeating Cold War–era failures where arms control did not prevent Soviet expansionism.

The Trump administration appears to be searching for a “third way” that transcends this binary choice. Taken together, NSS 2025 and the RNDF speech suggest four pillars of this emerging approach:

1) Strategic defensive advantage, centered on missile defense initiatives such as the Golden Dome

2) Deep-strike capabilities that enable precise attacks not only on frontline forces but also on command, control and logistics nodes deep within adversary territory, reinforcing deterrence in limited conflicts

3) Fixing geographic asymmetry through the maintenance of U.S. dominance in the Western Hemisphere

4) Modernized nuclear deterrence combined with crisis management mechanisms, rather than reliance on vulnerability alone

This represents an attempt to construct a multilayered deterrence architecture suited to the “two-peer” era. Yet significant challenges remain, including costs, technological maturity and the implications for strategic stability. Transparency and crisis management frameworks are essential to mitigate security dilemmas, but concrete measures have yet to be articulated.

Deep-strike capabilities against near-peer adversaries also pose operational challenges. Nevertheless, strategic bomber patrols already function as flexible signaling tools in peacetime, and limited, restrained strikes — such as against maritime targets — could theoretically serve as controlled escalation options. Because strategic defensive advantages will take time to mature, maintaining a degree of strategic stability with China remains necessary in the interim. Hegseth’s remarks implicitly acknowledge this balance. Still, an overly hasty pursuit of stability risks legitimizing a de facto division of spheres of influence among the U.S., China and Russia — potentially encouraging further expansion by Beijing and Moscow.

Western Hemisphere primacy

While nuclear parity between the U.S. and China may stabilize strategic nuclear relations, it can simultaneously heighten the risk of limited conflicts in the Taiwan Strait and the South China Sea. Preventing such scenarios requires linking U.S. escalation management with allied trigger mechanisms for extended deterrence. This is because deterrence credibility rests not on declaratory commitments alone, but on demonstrable capabilities and integrated joint operations that convince adversaries victory is unattainable.

In this context, the Trump administration’s emphasis on Western Hemisphere primacy represents a revival of a foundational U.S. strategic principle. During the Cold War, uncontested U.S. dominance in the Western Hemisphere created a form of geographic asymmetry that shaped Soviet calculations. Reasserting this dominance could again serve as a strategic signal to China and Russia.

At the same time, “America First” policies risk undercutting this advantage by fueling alliance fragmentation and information warfare. To translate Western Hemisphere primacy into credible extended deterrence, frontline allies — particularly Japan — must strengthen their own autonomous denial capabilities, institutionalize trigger mechanisms for extended deterrence and ensure rapid decision-making and operational integration in crises. For instance, Japan’s development of long-range anti-ship strike capabilities as a form of decisive denial, combined with coordination with U.S. deep-strike forces operating from Australia and the United States, could significantly enhance deterrence credibility.

Ultimately, deterrence in the “two-peer nuclear” era cannot rest on a simple choice between superiority and parity. It requires an integrated design that combines capabilities, institutions and alliance cooperation into a coherent whole.

© The Japan Times