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Introduction

Guam, “where America’s day begins,” constitutes an indispensable strategic hub for the United States. The largest of the Mariana Islands in the western Pacific, it allows the United States to successfully project power within the Indo-Pacific region and so makes credible US security commitments to key US allies located there. Guam is home to Andersen Air Force Base (AFB), from which F-22 Raptors and strategic bomber rotations project US power from the skies, and to the deep-water port Apra Harbor, which plays a critical role in US Navy missions aimed at keeping trade routes open. Thus, this US territory is essential to the security of the American citizenry.

Guam’s great strategic value to the United States and its proximity to North Korea and the People's Republic of China (PRC) make it a prime target of missile attack by these US adversaries. Of particular concern, however, is the threat posed by possible Chinese long-range missile strikes, and so, to enable the successful projection of US power within the region and provide credible assurance to key allies, Guam’s defenses must be strengthened. Due to its significance to US security and its status as a US territory, military officials have increased their emphases on the need to speed up the construction of an adequate defense. Then-Commander of US Pacific Command Admiral Davidson regularly connected Guam to the US homeland, stating to Congress, “Hawaii, Guam, and our Pacific territories are part of our homeland and must be defended.”¹

The PRC seeks to supplant the United States as the world’s preeminent power,² and one key to achieving this ambition is transforming the Indo-Pacific from a free and open region under the current US-led system into one that is Beijing-centric and Beijing controlled. China’s accomplishing this would not only prevent the US from ensuring the safe commerce in international waters that is essential to the health of the US economy but would also compromise the credibility of US security commitments to critical regional allies. Thus, China’s aims pose an unacceptable risk to American sovereignty and to the US ability to engage with sovereign nations freely and safely.

The likely flashpoint of a US-PRC military conflict is the PRC’s attempt to conquer democratic Taiwan. Although the United States has neither formal diplomatic relations nor a security agreement with Taiwan, denial of PRC ambitions to push the United States out of the region is strongly tied to the security and self-determination of a democratic Taiwan. Therefore, ensuring Taiwan’s self-rule has had strong bi-partisan support in Congress and across US administrations, as reflected in robust US weapons sales to Taiwan, military training assistance provided to Taiwan by the US, and meaningful symbolic political gestures of US support of and friendship with Taiwan.³ Director of National Intelligence Avril Haines stated, “It’s our view that (China is) working hard to effectively put themselves into a position in which their military is capable of taking Taiwan over our intervention” and that the threat to Taiwan between now and 2030 is “acute.”⁴

To support its national aims, the PRC has invested in a modern military designed specifically to counter key US military assets and bases located within the Indo-Pacific region. Xi Jinping has directed the Peoples Liberation Army (PLA) to completely modernize all weapons systems and all capabilities across all military domains by 2027. Of special concern is the PLA’s anti-access/area denial (A2/AD) strategic capability,⁵ whose purpose is to enable the PRC “to dissuade, deter, or, if ordered, defeat third-party intervention during a large-scale, theater campaign such as a Taiwan contingency.”⁶

In addition to the rapid development of the PLA’s conventional weapons, it is investing heavily in its nuclear weapons force. On September 2021, Commander of US Strategic Command Admiral Charles Richard described the PRC as engaging in a “strategic breakout,” i.e., “a rapid qualitative and quantitative expansion of military capabilities that enables a shift in strategy” necessitating “the DoD to make immediate and significant planning and/or capability shifts.”⁷ Recently, Admiral Richard also warned of the “cooperative aggression” posed by Russia and the PRC working in concert.⁸

If deterrence were to fail and the PRC were to attempt to take Taiwan by military force, Guam would constitute a critical forward location for US actions to defend it in collaboration with US allies.

Given Guam’s strategic importance and the threat to its security that the PRC represents, the US has a clear and vital national interest and an obligation to ensure Guam’s protection. Therefore, inspiring and contributing to public consideration of and debate about the importance of Guam’s defense are essential, and this compilation of essays and the associated two-part panel discussions contribute to this endeavor. In them, scholars who have devoted research and analysis to difficult challenges facing policymakers and defense planners and who represent a wide range of knowledge, expertise, and diverse viewpoints address various aspects of the PRC challenge and suggest approaches to address Guam’s vulnerability. These scholars agree on some key aspects of the threat the PRC poses and the consequent challenge facing the United States but at times emphasize varying aspects of the challenge and propose differing orders of priority in meeting these challenges.
The elements of my working thesis concerning Guam’s defense are seven-fold.

One, this defense must cover 360 degrees and incorporate “depth.” PLA threats to Guam will originate from air, sea, and land and come from all directions; therefore, Guam’s defense must include an architecture extending to the sea and to other islands within the Mariana Island chain.

Two, this defensive architecture cannot be held to a “zero-leak” standard. The quantity of missiles the PLA now has renders a zero-leak requirement infeasible, making any attempt to adhere to this standard unnecessary. Instead, the aim should be to quickly build out Guam’s 360-degree coverage and enable the integration of various sensors, thereby demonstrating US commitment to fight for and from Guam and so communicating to the Chinese that a quick victory over Guam is impossible.

Additionally, if the United States can intercept and render useless incoming weapons, it will have the ability to retaliate with a robust counter-offensive. One of the most promising strategies for achieving a high kill rate without attempting to adhere to a zero-leak standard is for military defenders to have a clear picture of the threat so as to mount an effective defense and retaliate appropriately. Missile Defense Agency (MDA) Director Vice Admiral Hill stated that his aim is integrating multiple data streams into a coherent picture for military commanders, the most challenging aspect of Guam’s defense. Thus, the MDA has prioritized construction of an integrated missile defense command and control center on Guam.⁹ However, it is imperative that this command center give commanders a full picture of the battlespace across domains and offer management of the fight beyond defense and across services and functions.

Three, while passive defenses including tactics intended to deceive an adversary and fortification of military infrastructure to sustain an attack are important, there is no substitute for a layered active defense. To achieve cost-effectiveness, some budget offices may be tempted to over-rely on passive defenses, but that would be a grave mistake. The US military must have the ability to blunt the impact of a fast PRC attack, and that means preventing missiles from hitting key targets.

Four, a distributed defensive architecture is crucial. Complicating the adversary’s calculations about how it might subdue US forces on Guam is key to strengthening deterrence and successfully thwarting the enemy’s attack if deterrence fails. Still, though Guam is the largest of the Mariana islands, it has an area of only 200 square miles. Less than half of it is controlled by the Department of Defense, and thus the number of locations for emplacement of military equipment, both offensive and defensive, that it can provide is limited. During an ongoing barrage of incoming fires, the requirement that defensive systems are mobile might not be operationally practical, even if theoretically desirable; from conversations with operators, the most important attribute required for defensive systems is persistency.

Five, time is not on our side, and immediate development and implementation of a Guam defense strategy is essential. Policymakers and defense planners must not permit bureaucratic inertia or micromanagement by such budget entities as the Cost Assessment and Program Evaluation (CAPE) office to determine the order and sequence of critical steps in construction of Guam’s defenses. Instead, national policy must drive this strategy and budget.

Six, rapid, regular, and visible tests of Guam’s offensive and defensive systems serve the important purpose of signaling to the PRC that the United States is willing and able to defend its territory and to follow through on its security commitments. There is no evidence that highly visible or frequent testing will “provoke” the PRC to attack. To the contrary, visible and realistic tests of offensive and defensive systems on land and at sea could persuade the PRC not to attack, since the presence and viability of these systems would weaken the PRC’s assessment of its likelihood to succeed. The Pentagon has therefore outlined “campaigning” as one of its three aims for implementing its Defense Strategy.¹⁰ Visible and frequent testing of the capabilities needed in a direct confrontation with the PRC under realistic scenarios is exactly the kind of campaigning required to persuade the PRC that now is not a good time to launch an attack.

Seven, policymakers should educate the American public on the integral role the US territory of Guam plays in the security of the United States and in the American way of life. A lack of support domestically to fight from and for Guam could convey a lack of political will on the part of US government officials. It is wise to make efforts publicly, in rhetoric (for example, Admiral Davidson’s effort to describe Guam’s defense as “Homeland Defense System Guam.”¹¹), and in other ways such as senior US official visits to Guam.

In conclusion, maintaining a free and open Indo-Pacific theater constitutes a vital US interest and a necessity for the credible provision of US assurances and commitments to key US allies in the region. These US security guarantees, backed by US resolve and military power, underpin the US-led order regionally and globally. Moreover, not only is Guam a key strategic hub and so vital to American security and prosperity, but it is also a US territory and home to US citizens. Guam’s defense is therefore imperative. Fighting from and for Guam is challenging but eminently achievable, and its defenses must be strengthened now to dissuade the PRC from initiating aggressions against it in pursuit of one of its national priorities, the conquest of a democratic Taiwan. However, time is not on our side, and we must therefore move quickly.