Sure about that? Through the Secretary of State, the State Department. I would be surprised if he could not. Expulsion.
But, if I understand it correctly, in Afroyim v. Rusk (1967), the Supreme Court ruled that the U.S. government cannot revoke a citizen’s citizenship without their consent. The case involved a naturalized American who voted in a foreign election, and the Court held that the 14th Amendment protects citizenship as a fundamental right—one that can’t be taken away by the government, even if the person engages in actions abroad.