[Tervuren]

You're thinking in terms of conventional warfare between AI and humans.

The AI doesn't have to use conventional warfare, it just has to turn us against ourselves.
And when it does it, it will be smart enough we won't even know to pull the plug.
Humans are irrational first, and if rational at all, it is generally an afterthought to justify your actions to other people. Only a small amount of human action is based on rationality.
Which makes us excellent marks for an AI to exploit.