How Trump's team could've planned the Houthi strikes without Signal

What they're saying: "It's shocking. It's shocking negligence," a former senior defense official said. "We've got the best secure communication systems in the world — of any country — so why are we using a rickety, commercially available system?"

• The former official said Signal is "not even in the same universe" as the Pentagon's JWICS intranet, through which some of the country's most delicate intelligence is shared.
• Set aside the fact that a prominent journalist was privy to the group chat. Sending a minute-by-minute timeline of impending strikes over a network you can't be sure is fully secure endangers pilots and could compromise the success of an operation, the former official contended.

The other side: The White House insists there was nothing wrong with officials using Signal, which is end-to-end encrypted and is widely used by private citizens (such as journalists) to share sensitive information and gossip.

• White House Press Secretary Karoline Leavitt called the app "the most secure and efficient way to communicate."
• But security experts consider communicating via Signal, particularly from a personal device, far less secure than using a classified government channel.
• The White House and National Security Council did not respond to requests for comment.

Friction point: A current senior U.S. official told Axios that while many of the participants in the Signal chat have encrypted government-issued phones on which they can discuss classified information, poor reception and other technical problems can make using a personal device easier. "You can drop from the line in the middle of a call," the official said.

• A former State Department official noted that various government agencies use different brands of secure devices — State's is nicknamed a "Puma phone" — which can create problems when communicating across departments.
• A former senior Pentagon official said that rather than communicating via text, officials typically got a notification to switch to their classified devices in order to join a conference call. While a chat feature was added to the secure devices toward the end of the Biden administration, it was not widely used, the official said.
• Jamil Jaffer, who held intelligence-related roles in the White House and Congress, said the fact that officials were using Signal was a sign that onerous security protocols "make it impossible to do your job" — or at least to do it efficiently.

Despite the headaches, the former officials who spoke to Axios were in agreement that sharing detailed attack plans in a Signal group chat was highly unusual and irresponsible.

• While both Defense Secretary Pete Hegseth and national security adviser Michael Waltz have contended that they didn't share "war plans," only attack plans, the former defense official argued that the specificity of those messages was "far more damaging" than discussing war plans, which can be broader and more flexible.
• Texts Hegseth sent about two hours before key aspects of the operation commenced specifically mentioned manned and unmanned aircraft, F-18s and MQ-9s, as well as sea-launched Tomahawk missiles, which travel relatively slowly.

• Price Floyd, a former head of public affairs at the Pentagon, raised particular alarm over a text from Waltz about a top Houthi target entering his girlfriend's apartment building. "That will put all of the people she spoke with, met with, etc. at risk of being [identified as] a possible source of the intel."

Flashback: Coordination around previous strikes on the Houthis in January 2024 were done mainly over classified emails, either on a "secret" or "top secret" system, a former senior defense official who was involved in planning those strikes said.

• A detailed plan of attack like the one Hegseth texted would normally remain internal to the Pentagon and not be shared with Cabinet-level policymakers, even in a secure setting.

Behind the scenes: The planning didn't all take place on Signal. The current senior U.S. official told Axios the key meeting President Trump held on the Yemen operation — including with some of the officials on the Signal chat — took place in the Situation Room a day after the messaging app group was established.

• Last Saturday, Trump gave the final order and followed the strike from a Sensitive Compartmented Information Facility (SCIF) in Mar-a-Lago, the official said.
• In the meantime, though, officials including Waltz, Hegseth and Vice President Vance were debating the merits of the operation and discussing its details over Signal, with Atlantic editor Jeffrey Goldberg following along.
• Those conversations didn't need to happen on Signal, or on personal mobile devices. The current official noted that many of the officials on the Signal chat have SCIF's in their homes, making moving to a classified setting relatively straightforward.

Go deeper: Fact-checking the explanations over Houthi group chat.