While #Signal is perfectly fine for private conversations between non PEP (political exposed), or even private conversations between these, it is not OK when used for national security matters..
PEPs are typically high profile surveillance targets, blackmailing. Just loosing a phone can be disastrous if it is not remotely wiped immediately.
Hegseth shows disrespect for the lives of servicemen/women.
https://edition.cnn.com/2025/04/20/politics/hegseth-second-signal-chat-military-plans/index.html

Hegseth shared detailed military plans in second Signal chat that included his wife and brother
Secretary of Defense Pete Hegseth shared detailed plans about a military operation against the Houthis in Yemen on a second Signal group chat that included his wife, lawyer and brother, three people familiar with the chat told CNN.