campaign slogan for emperor Augustus?

Based on when he became Emperator, the one thing he had really done was win the wars against his challengers and restore order. Order was the bigt thing, and defeating Rome's "enemies".
So I would make it about his military victories, as that was what really won him the throne of Rome.

"I found Rome brick and left it marble."

Augustus Caesar, the Roman Geezer.

"There's no Denial: We Now Control the Nile."