Elbridge Colby
Under Secretary of Defense for Policy Presumptive nominee
Assuming office TBD
President	Donald Trump (elect)
Succeeding	Amanda J. Dory
Deputy Assistant Secretary of Defense for Strategy and Force Development
In office 2017–2018
Personal details
Born	Elbridge Andrew Colby[1] (1979-12-30) December 30, 1979 (age 45)
Political party	Republican
Relatives	William Colby (grandfather)
Education	Harvard University (BA) Yale University (JD)

Elbridge A. Colby (born December 30, 1979) is an American national security policy professional who served as Deputy Assistant Secretary of Defense for Strategy and Force Development from 2017 to 2018 during the Trump administration. He played a key role in the development of the 2018 U.S. National Defense Strategy, which, among other things, shifted the U.S. Defense Department's focus to challenges posed by China's rise.

In June 2018, Colby was appointed as Director of the Defense Program at the Center for a New American Security (CNAS). In 2019 he co-founded The Marathon Initiative with Wess Mitchell. In December 2024, President-elect Trump nominated Colby to serve as the Under Secretary of Defense for Policy.

Colby graduated from Harvard College in 2002, and from Yale Law School in 2009.^[2][3] His early career included over five years of service with the Department of Defense, the Department of State, and in the Intelligence Community, including a period of service with the Coalition Provisional Authority in Iraq in 2003.^[2][4] Colby also served in the Office of the Director of National Intelligence during its stand-up in 2005–2006.^[4]

From 2010 to 2013, Colby worked as an analyst at CNA, a federally funded nonprofit research and analysis organization. From 2014 to 2017, Colby was the Robert M. Gates fellow at the Center for a New American Security.^[5] In 2015, Colby was considered for a top job in Jeb Bush's 2016 presidential campaign, but was not hired after "prominent, interventionist neoconservatives" objected.^[3][6]

In May 2017, Colby was appointed the Deputy Assistant Secretary of Defense for Strategy and Force Development, a role in which he served into 2018.^[3] In this role, Colby was responsible for defense strategy, force development, and strategic analysis for policy for the Secretary of Defense.^[2] Colby served as the primary Defense Department representative in the development of the 2017 National Security Strategy.^[7]

While Deputy Assistant Secretary, Colby served as the lead official in the development and rollout of the department's strategic planning guidance, the 2018 National Defense Strategy (NDS). The NDS posited: "Inter-state strategic competition, not terrorism, is now the primary concern in U.S. national security," and "the central challenge to U.S. prosperity and security is the reemergence of long-term strategic competition," primarily from China and Russia.^[8] Going further, Colby said the "central challenge facing the department of defense and the joint force [is] the erosion of U.S. military advantage vis a vis China and Russia."^[9]

Politico reported that in re-orienting American defense resources away from the Middle East and towards China, Colby faced considerable bureaucratic infighting from U.S. Central Command and the Joint Staff, but received support from the Air Force and the Navy.^[3]

After leaving the Department of Defense in 2018, Colby returned to the Center for a New American Security (CNAS), where he continued to work on defense issues until 2019.^[10] He then launched The Marathon Initiative, a think tank devoted to developing strategies for the US to compete with global rivals.^[3][7][11]

In 2021, Colby expanded on his views in his first book, The Strategy of Denial: American Defense in an Age of Great Power Conflict, which The Wall Street Journal named a Ten Best Book of 2021.^[3][12]

On December 22, 2024, President-elect Trump nominated Colby to serve as the Under Secretary of Defense for Policy for his second term as president.^[13]

Colby identifies as a realist. He believes that China is the principal threat faced by the United States, and that Asia should be the priority of U.S. efforts and resources.^[14] He advocates for the U.S. to shift its military planning and resources to prepare for a conflict over Taiwan, and supports bolstering U.S. industrial capacity.^[3][14] In a Time article he co-authored with Heritage Foundation President Kevin Roberts, Colby wrote that: "[W]e need to be absolutely clear: Without question, the top external threat to America is China—by far."^[15] He is a "prioritizer", believing the U.S. to have limited military resources, and thus supporting a reorientation of U.S. military resources away from the Middle East and Europe to Asia and China.^[16] Foreign Policy describes him as "the loudest and perhaps most cogent voice in Washington advocating a complete shift away from Europe, NATO, and Russia and toward the growing challenge from China".^[17]

Colby believes China is seeking regional hegemony over Asia, which he believes to be the world's most important region, and will achieve that goal if not stopped by the U.S. He says that if China is allowed to dominate Asia, it would severely diminish America's future prospects and freedom of action, push the American economy down the value chain, and lead the U.S. less resistant to Chinese pressure.^[14][17] He believes the best way China would achieve regional hegemony would be by attacking a U.S. ally or quasi-ally, which he identifies as Taiwan. He advocates for a "strategy of denial" to deny regional hegemony to China and stopping or defeating a potential invasion of Taiwan. He believes the best way China would achieve this would be by attacking a U.S. ally or quasi-ally, which he identifies as Taiwan. He believes an attack on Taiwan would lead to a "limited war" which would seek to cause the least upheaval in the region, with no motivation on either side to escalate; he calls on the U.S. to prepare for this scenario. He further calls for a "anti-hegemonic coalition" made up of U.S. allies in Asia to stop China from taking over Taiwan; he believes if the coalition failed to stop a takeover of Taiwan, China could next seize the Philippines and Vietnam. He also advocates for an end to U.S. policy of strategic ambiguity on Taiwan.^[14][18]

Despite his reputation as a China hawk, he does not describe the Chinese Communist Party or Chinese leader Xi Jinping as "evil" and rejects "cartoonish account" of China as "unstoppably rapacious", believing China to be a "rising power" with "a rational interest in expanding their sphere and believing themselves to be aggrieved and put upon". He supports treating China with respect and a "strong shield of disincentive", continuing by saying that his policy is "status quo. My strategy is not designed to suppress or humiliate China… I believe China could achieve a reasonable conception of the rejuvenation of the great Chinese nation, consistent with the achievement of my strategy. If you put all that together, that looks like somebody who is advocating for peace based on a realistic reading of the world."^[14] He also believes the U.S. should not seek to change China's internal politics or ideological system as long as China does not seek regional hegemony.^[18]

Colby supports deprioritizing North Korea, telling Yonhap News Agency in May 2024 that the "fundamental fact is that North Korea is not a primary threat to the U.S." and it "would not be rational to lose multiple American cities to just deal with North Korea".^[19] He called on South Korea to take "overwhelming responsibility" for its own defense against North Korea, with the U.S. getting involved only if China gets involved. He also said United States Forces Korea should be focused on protecting South Korea from possible Chinese attacks instead of being "held hostage to dealing with the North Korean problem". He supports transferring wartime operational control from the U.S. to South Korea, while signaling his openness to South Korea acquiring nuclear weapons. He said the denuclearization of North Korea was an "impossibly far-fetched" idea, instead calling to focus on more "attainable" goals such as arms control focused on limiting the range of North Korean intercontinental ballistic missiles.^[20] He advocates Japan to spend more on its military, telling The Nikkei in September 2024 that Japan should 3% of its GDP on military.^[21]

Colby believes aiding Ukraine during the Russian invasion of Ukraine jeopardizes America's focus to China, and this reality necessarily means America must prioritize investment of attention and resources on China, including a reduction in support for Ukraine. In 2023, he told Politico that "Ukraine should not be the focus. The best way to avoid war with China is to be manifestly prepared such that Beijing recognizes that an attack on Taiwan is likely to fail. We need to be a hawk to get to a place where we can be a dove. It’s about a balance of power".^[3] Colby later wrote that "it is in America's interest to avoid [Ukrainian defeat], but we must pursue that interest in a manner consistent with our highest priority of restoring a formidable denial defense along Asia’s first island chain."^[22] He rejects Ukraine's membership to NATO.^[23] Colby instead supports European countries to commit more resources on countering Russia and bolstering their militaries, allowing the U.S. to shift its resources on Asia.^[14] He believes European NATO members should spend around 3 to 4 percent of their GDP on defense and says the U.S. should be "prepared to use carrots and sticks to incentivize the right kind of behavior from our point of view" in regards to European countries.^[24]

Colby supports a reduction of U.S. military presence in the Middle East, a region which he described as "relatively unimportant" from a geopolitical standpoint. He supports withdrawing the U.S. military from the Persian Gulf, arguing the U.S. can counter Iran "more efficiently" by "bolstering the military capabilities of its partners in the region". He opposes direct military action against Iran, while arguing that containing an Iran with nuclear weapons "is an entirely plausible and practical objective. In an article written shortly before the 7 October Hamas-led attack on Israel, Colby called for a "reset" in America's relationship with Israel, saying America should "defer more to Israel's judgement about how to best manage its security challenges", and that while the US should be prepared to provide material and political support to Israel, it should understand that the US., which "cannot afford to be enmeshed in another Middle Eastern war, will take a supporting role." He later questioned Biden administration's efforts to counter the Houthis in Yemen.^[16]

• The Strategy of Denial: American Defense in an Age of Great Power Conflict (Yale University Press, 2021)^[25][26]

• The United States should prioritize Taiwan over Ukraine, a 2023 opinion piece by Colby and Alex Velez-Green in The Washington Post
• The Tragedy of Foreign-Policy Realism by Malcom Kyeyune
• Elbridge Colby on Multipolarity Podcast