WASHINGTON — President Trump returned on Monday to his post-impeachment score-settling, withdrawing the nomination of Elaine McCusker to a top Defense Department post. Ms. McCusker had questioned the suspension of assistance to Ukraine, a central line of inquiry in the president’s impeachment.

White House aides had forecast the punishment for Ms. McCusker last month, around the time the president was banishing Alexander S. Vindman and Yevgeny Vindman, twin brothers and both Army lieutenant colonels, from the National Security Council. Alexander Vindman testified during Mr. Trump’s impeachment proceedings.

Mr. Trump also fired Gordon D. Sondland, his ambassador to the European Union, who famously asked and answered his own question during the impeachment hearings: “Was there a quid pro quo? The answer is yes.”

News outlets reported that Ms. McCusker was next on the chopping block. Administration officials said they expected the paperwork for her nomination to be comptroller at the Pentagon to be pulled after budget hearings.