As you may notice, in that Garrison Center column, I throw in a lot of "thought to be" and "allegedly" stuff, because while the consensus theory of what happened is plausible, it's not the only obvious possibility. I can think of three:
- That consensus theory: National security adviser Mike Waltz inadvertently added Jeffrey Goldberg, editor in chief of The Atlantic, to a Signal chat involving himself, Secretary of Defense Pete Hegseth, Director of National Intelligence Tulsi Gabbard, Secretary of State Marco Rubio, and others, regarding "sensitive national security matters," namely plans for US military strikes on Yemen.
- Waltz intentionally added Goldberg for some administration or personal purpose -- maybe to leak the plans to a journalist who would almost certainly wait until after the fact to publicize them and make the administration look simultaneously thoughtful and decisive, maybe to make one or more of the participants look good or bad, whatever.
- Someone other than Waltz (maybe even Goldberg) nefariously added Goldberg to the chat in hopes of frustrating the plans or making Waltz, or one or more of the other participants, look incompetent or evil.
I tend to discount possibility #3, since it seems more technically challenging because it implies "hacking" or something similar.
But possibility #2 isn't some kind of far-out hypothesis. Administrations intentionally leak stuff all the time.