What is a "decisive strategic advantage"?

We say an agent has a decisive strategic advantage if it is in a position of superiority that allows it to take control of the world.

In the past, different nations have sometimes been ahead of all others in economic, military, cultural, and technological power, but none have ever effectively been unopposed, and conquest might have been possible but would always have come at a heavy cost.

A misaligned AI could attain a decisive strategic advantage as a result of being superintelligent, which could lead to an AI takeover. Even an aligned superintelligence could be used by whoever controls it to impose their will on the rest of the world.