Former White House national security adviser H.R. McMaster said at a Foundation for Defense of Democracies event on Thursday that it's "absolutely not" appropriate for the president to solicit foreign election interference, but that it's up to Congress to decide whether he did so with Ukraine.

REPORTER: "Is it appropriate for the president of the United States to solicit foreign interference in our political process?"

MCMASTER: "Of course no. No, it's absolutely not. And of course, what has to happen here is seeing our democracy play out, our separation of powers play out. And for the American people, through their representatives in Congress, to make a judgment of whether that happened."

Why it matters: Trump is facing an impeachment inquiry over allegations that he pressured the Ukrainian government to investigate Joe Biden. McMaster, a 3-star general who served as the 2nd of Trump's 4 national security advisers, was widely considered one of the more responsible high-ranking officials to serve in the president's inner circle — part of a loose alliance in the early days of the Trump presidency that saw it as their duty to protect the nation from disaster.

Go deeper: Trump's trifecta of calling on foreign powers to interfere in elections