In this Jan. 27, 2020, file photo Army Lt. Col. Alexander Vindman, a military officer at the National Security Council who testified during the impeachment hearings on Capitol Hill, walks down the steps of the Eisenhower Executive Office Building on the White House complex in Washington. Vindman who was a pivotal witness in the first impeachment case against Donald Trump has sued the oldest son of the former president and other Trump allies, accusing them of participating in an “intentional, concerted campaign of unlawful intimidation and harassment” over his decision to testify. The suit from Vindman was filed Wednesday, Feb. 2, 2022, in federal court in Washington. (AP Photo/Susan Walsh, File)