https://www.techdirt.com/articles/20220116/11335048296/because-defense-departments-secure-communications-options-dont-work-everyone-soldiers-are-turning-to-signal-whatsapp.shtml

The military has an obvious need for secure communications. It offered its support of encryption even as the NSA tried to find ways to undercut to make its surveillance ends easier to achieve.

The problem is the military doesn't have a great plan for securing communications between personnel. Due to tech limitations the Defense Department has yet to overcome (despite billions in annual funding), soldiers are turning to third-party messaging services to communicate orders and disseminate information.