President Trump and Defense Secretary Pete Hegseth in the Oval Office on March 21. Photo: Anna Moneymaker/Getty Images.

Members of Congress in both parties exploded in anger Monday after the editor-in-chief of The Atlantic revealed he was inadvertently included in a highly-sensitive Trump administration Signal chat on airstrikes in Yemen.

Why it matters: Some Democrats are already calling for an investigation and potential repercussions against the national security officials involved in the lapse.

• “This is an outrageous national security breach and heads should roll,” Rep. Chris Deluzio (D-Pa.), a member of the Armed Services Committee, said in a statement to Axios.
• He added: “We need a full investigation and hearing into this on the House Armed Services Committee, ASAP.”
• “We can’t chalk this up to a simple mistake – people should be fired for this,” said Rep. Sara Jacobs (D-Calif.), another Armed Services Committee member.

Between the lines: People identifying as Defense Secretary Pete Hegseth, National Security Adviser Michael Waltz and Vice President Vance were among the 18 people in the Signal chat, per The Atlantic’s Jeffrey Goldberg.

• “At this time, the message thread that was reported appears to be authentic, and we are reviewing how an inadvertent number was added to the chain,” National Security Council Spokesman Brian Hughes said in a statement.
• “The thread is a demonstration of the deep and thoughtful policy coordination between senior officials. The ongoing success of the Houthi operation demonstrates that there were no threats to our servicemembers or our national security,” Hughes said.

Zoom in: Rep. Don Bacon (R-Neb.), another Armed Services Committee member and a former Air Force brigadier general, told Axios, “I’ve accidentally sent the wrong person a text. We all have.”

• But, he added, “The unconscionable action was sending this info over non-secure networks.”
• “None of this should have been sent on non-secure systems. Russia and China are surely monitoring his unclassified phone,” Bacon said.

The bottom line: Sen. Mark Warner (D-Va.), the top Democrat on the Senate Intelligence Committee, posted on X: “This administration is playing fast and loose with our nation’s most classified info, and it makes all Americans less safe.”