Mike Waltz, the former national security adviser who left his position in May in the wake of the Signal chat controversy in March, is facing a confirmation hearing Tuesday on Capitol Hill for his nomination as United Nations ambassador.

Former national security adviser Mike Waltz defended his use of the messaging app Signal during a confirmation hearing Tuesday during which lawmakers largely avoided the topic.

Michael Waltz, the former national security adviser, doubled down on the Trump administration’s defense of a Signal group chat where senior officials discussed war plans.