Like what happened to China after they released Tiktok, or what happened to Russia after they used their troll farms to affect public sentiment surrounding US elections?
"Flooding social media" isn't something difficult to do right now, with far below state-level resources. AIs don't come with built-in magical account-creation tools nor magical rate-limiter-removal tools. What changes with AI is the quality of the message that's crafted, nothing more.
No military uses tweets to determine if it has been nuked. AI doesn't provide a new vector to cause a nuclear war.