U.S. Army Lieutenant Colonel Alexander Vindman should not fear retaliation over his testimony to the U.S. Congress in its impeachment inquiry into President Donald Trump, Defense Secretary Mark Esper told a small group of reporters on Monday.
Vindman, now detailed to the White House National Security Council, has been targeted by Trump following his Oct. 29 congressional testimony. Trump tweeted that Vindman was a "Never Trumper witness," raising questions about potential fallout on his military career.
"He shouldn't have any fear of retaliation," Esper said during a flight to New York, adding he had reinforced the "no retaliation" message in a conversation with the secretary of the Army.
Vindman was among the U.S. officials in the White House monitoring Trump's call on July 25 with Ukraine President Volodymyr Zelenskiy, a main focus of the impeachment probe in the Democratic-led U.S. House of Representatives.
According to a transcript of his testimony, Vindman said he had no doubt that Trump demanded that Ukraine investigate political rival Joe Biden in return for an Oval Office visit for the Ukrainian leader.
"This was about getting a White House meeting," Vindman said in his testimony. "It was a demand for him to...fulfill this particular prerequisite."
Vindman told lawmakers that he believed ties between the U.S. and Ukraine have been damaged by the administration's actions.
"It undercuts U.S. resolve to support Ukraine and certainly puts a question into their mind whether they in fact have U.S. support," Vindman said.
Democrats, who control the House, have argued that Trump abused his power in pressing a vulnerable U.S. ally to carry out investigations that would benefit Trump politically.
Biden is a leading contender for the Democratic nomination to face the Republican president in the 2020 election. His son Hunter Biden served on the board of a Ukrainian energy company called Burisma.