A spokesperson for Denver Mayor Mike Johnston admitted this week that the office has been operating an internal group on the encrypted messaging app Signal that was monitoring news stories and had been auto-deleting the group's messages.

Illinois Gov. JB Pritzker asked the Joint Chiefs of Staff for assurances about steps being taken to protect national security after sensitive plans were shared on Signal.

President Donald Trump’s national security advisor, Mike Waltz, has repeatedly landed in hot water in recent days, beginning with an uproar from Democrats over a Signal chat leak with high-ranking national security officials that has since snowballed,

Jeffrey Goldberg joins Ashley Parker to discuss breaking the Signal story, the fallout, and more. Don’t miss this subscriber-only event on Thursday, April 3, at 11:30 a.m. ET.