McMaster is a retired U.S. Army lieutenant general, who served as the 25 th United States National Security Advisor from 2017 to 2018, under Trump. He is currently a senior fellow at the Hoover Institution at Stanford University. Newsweek reached out to McMaster via email for further comment.

Ahead of Volodymyr Zelensky's visit to the U.S. this week, his aides and allies tried to shape Donald Trump's views on Ukraine

"I would appeal to his sense of, 'Don't be a loser,'" Rep. McCaul says he'd tell Trump regarding aid to Ukraine. "You don't want to lose this."