The Pentagon's top policy official on Tuesday described North Korean and Russian nuclear weapons as the "primary existential threat," while stressing America is "not pulling out" but asking allies to "take the lead" for their own defense. Under Secretary of Defense for Policy Elbridge Colby made the remarks during a hearing of the Senate Armed Services Committee on the Pentagon's new National Defense Strategy (NDS), which stresses burden sharing with allies and calls on Seoul to take "primary" responsibility to deter North Korea with "critical but more limited" U.S. support. Colby rejected the lingering notion that the NDS — with an emphasis on defending the U.S. homeland, the Western Hemisphere and deterring China — signals a diminished U.S. intent to deter threats posed by Pyongyang and Moscow. "I don't at all. ... In fact, I think the NDS details, and it does so from a realistic perspective that matches our perspective. ... Obviously, the primary existential threat posed by Russian and North Korean nuclear weapons," the official said. He added that the basic logic of the strategy