Christopher C. Miller

Miller's tenure in the Trump administration began as Director of the National Counterterrorism Center, confirmed by voice vote in the United States Senate on August 6, 2020. President Donald Trump named Miller acting defense secretary after firing Mark Esper on November 9, 2020, six days after the 2020 presidential election. Miller was accused of obstructing the transition to Joe Biden's administration by Biden staff, which Miller denied.
Miller was criticized for his response to the 2021 storming of the United States Capitol. He approved the deployment of National Guard troops from neighboring states to reinforce the D.C. National Guard at 4:41 p.m., three hours after Capitol Police said that they were being overrun and two hours after city officials had asked for such assistance. Miller later testified that he had no need to speak with the president on January 6 because, "I had all the authority I needed and I knew what had to happen," and he said the delay was because he wanted to avoid a repeat of the Kent State shootings.
Upon the inauguration of Joe Biden on January 20, 2021, Miller was succeeded by then-Deputy Secretary of Defense David Norquist. Provided by Wikipedia