Mr. Huang has been under scrutiny for an affair with a woman said to be a Chinese spy, as well as a relationship with an executive at his A.I. chip company.
The upheaval points to a broader dilemma spurred by the election: whether the department can carry out President Trump’s priorities as career officials eye the exits and senior department officials resign.
Representative Thomas Massie, the Kentucky Republican, said he would use his waning time in office to prod his party to vote for “sanity” and break with President Trump.
An expanding legal fight over the proposed site of President Trump’s 250-foot triumphal arch looms over his visit to Arlington National Cemetery on Veterans Day.