Elbridge Colby

Elbridge Andrew Colby (born December 30, 1979) is an American national security policy professional who is the under secretary of defense for policy since April 9, 2025. He previously served as deputy assistant secretary of defense for strategy and force development from 2017 to 2018 during the first 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 China. He is the grandson of former CIA director William Colby. 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, a grand strategy think tank, with Wess Mitchell. In December 2024, President-elect Donald Trump nominated Colby to serve as the under secretary of defense for policy in the second Trump administration. Identifying as a realist, Colby believes China is the principal threat faced by the United States. He believes the US should shift its military resources to Asia to prevent a Chinese takeover of Taiwan. Colby supports reducing military aid to Ukraine. During the AUKUS review in 2025, Colby pressured Australia to confirm what role it would play in a war with China over Taiwan.