NEW YORK (AP) — Donald Trump is naming longtime adviser Stephen Miller, an immigration hard-liner, to be the deputy chief of policy in his new administration.

Vice President-elect JD Vance posted a message of congratulations on Monday to Miller on X and said, “This is another fantastic pick by the president.” The announcement was first reported by CNN.

Miller was a senior adviser in Trump’s first term and has been a central figure in many of his policy decisions, notably his move to separate thousands of immigrant families as a deterrence program in 2018. Miller helped craft many of Trump’s hard-line speeches and plans on immigration.

Since Trump left office, Miller has served as the president of America First Legal, an organization of former Trump advisers fashioned as a conservative version of the American Civil Liberties Union, challenging the Biden administration, media companies, universities and others over issues such as freedom of speech and religion and national security.

Michelle L. Price, The Associated Press