Elbridge Colby led the drafting of the 2018 National Defense Strategy for the US. He is currently the Under Secretary of War for Policy in the US Department of War. This 2021 book (published by Yale University Press) provides insight into how Colby views strategy broadly, and US military strategy specifically. Colby is well read on Western military history and is creative in the scenarios he develops in the book. His approach appears to lack a depth of understanding of countries, peoples and coalitions outside the Euro-West, not of their history but their uses of agency and strategic thinking (his ideas reflect an imposition of American strategic thinking on others, which makes one question the nature of his creative scenarios). A reader today, in 2026, is somewhat puzzled with his role in the Trump administration (and strong defender thereof as well as his constant praise of President Trump). In this 2021 book he strongly recommended against a war with Iran (see notes below) and he placed a strong emphasis on coalition building. The current Trump administration, which he serves in, started a war against Iran and has weakened coalitions and alliances. (Colby says that others, such as the EU are paying more, that is not the point made) He places a strong emphasis on trust and credibility (there is an entire chapter in this book on its importance), which the world now questions. Notes:

“Readers will not find here any discussion of how to compete with China economically, how most international institutions should evolve, or any number of other problems in international politics. This is not because these are not important issues—they are—but because if Americans do not have the right defense strategy, these other considerations and interests will be forced to take a backseat. Figuring out that strategy is the task of this book.” (p. xii)

“The more plausible and thus compelling reason why the United States should be so concerned about regional hegemons is less direct but nonetheless implicates the fundamental purpose of ensuring a free and uncoerced national life and prosperity. If a state such as China could establish hegemony over a key region such as Asia, it would have substantial incentives to use its power to disfavor and exclude the United States from reasonably free trade and access to these wealthy regions in ways that would undermine America’s core purposes, shift the balance of power against the United States, and ultimately open the country to direct coercion in ways that would compromise Americans’ freedom, prosperity, and even physical security. This is because, if China could establish hegemony over Asia, it could then set up a commercial and trading bloc anchored in the world’s largest market that would privilege its own and subordinates’ economies while disfavoring America’s. The resulting drain on American businesses, large and small, would be most keenly felt by the workers, families, and communities who rely on those businesses for jobs, goods, services, and the other benefits that come with a vibrant economy. The steady erosion of America’s economic power would ultimately weaken the nation’s social vitality and stability.” (p. 10)

“The key element of a meaningful alliance facing an aspiring regional hegemon is that the alliance promises an effective defense of its members. The goal of the alliance is to defend a member state enough to keep it onside and contributing its part to the coalition. Effective in this context therefore simply means the denial of the conditions that would cause the targeted state to leave or stop contributing to the alliance and thus withdraw its strength from the coalition. These conditions, of course, depend on the nature and terms of a given alliance. But because it is about the will of the vulnerable state to continue to dedicate its power to the alliance’s—and thus the coalition’s—efforts, effectiveness is largely a relative and contingent, rather than an absolute, standard.” (p. 45)

“The cardinal implication of this book’s argument is that the United States should focus on making denial defense a reality in the Indo-Pacific with respect to its allies, including Taiwan. Preventing China’s regional hegemony there is the most important strategic objective of the United States; this goal should therefore receive strict priority in US defense planning and resourcing. Denial defense is the military strategy that most readily correlates the benefits of pursuing this aim with the costs and risks, and it is likely that a denial defense can work there if the United States and its allies and partners apply the needed level of effort and focus. Denial defense should therefore be the preferred standard for the United States and its allies with respect to China in the Indo-Pacific. Fortunately, the Defense Department’s 2018 National Defense Strategy has already steered the US Joint Force in this direction. Key regional allies such as Japan and Australia are also moving along similar lines… In concrete terms, the United States should focus first on an effective defense of Taiwan, the natural first target of China’s focused and sequential strategy. As outlined previously, Taiwan is militarily significant, given its location in the middle of the first island chain, and important for America’s differentiated credibility. Walking away from its defense would therefore significantly reduce the United States’ differentiated credibility as the external cornerstone balancer of an anti-hegemonic coalition. At the same time, Taiwan is likely defensible to the standard of an effective defense laid out in the book.6 Taiwan cannot be immunized from Chinese attack, but it likely can be protected from conquest. Ensuring an effective denial defense of Taiwan should therefore be the primary scenario the US Department of Defense uses to prepare US forces for the future, with a fait accompli attempt by Beijing serving as the primary focus of such planning. US forces should first and foremost be sized and shaped to ensure they can defend Taiwan successfully to the standard laid out previously. At the same time, Taiwan itself must significantly augment and improve its defenses and make itself more resilient.” (p. 236-7)

“There is no need for the United States to address a threat from Iran simultaneously to conducting a denial defense of Taiwan and maintaining its strategic deterrent, counterterrorism enterprise, and missile defenses. Iran’s conventional military is large and would present a formidable opponent if the United States wished to invade and occupy Iran, but doing so is not necessary to any US strategic interest and would almost certainly be a monumental and expensive mistake as well as a likely failure.” (p. 267)