President Trump's former national security adviser was pressed on the inclusion of a journalist on a sensitive group chat ...

Waltz is a former Green Beret and Florida representative who resigned from Congress to join the Trump administration. He ...

Waltz was removed from his job as national security adviser after he accidentally added a journalist to his Signal chat about an attack on Houthis.

Mike Waltz is facing questioning from lawmakers for the first time since he was ousted as national security adviser.

Former national security adviser Mike Waltz, testified before the Senate Foreign Relations Committee in his bid to become U.N. ambassador, stood by the use of Signal in a chat that discussed sensitive ...

Mike Waltz suggested the use of Signal was not only appropriate -- but actually prudent, given the guidance he was following.

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.

Sen. Cory Booker attacked former national security advisor Mike Waltz for not taking greater accountability for his role in a Signal group chat used to discuss strikes against the Houthis.

Defense Department guidance specifically prohibited employees from using Signal to transmit non-public information ...