Answer: the Government of the greatest Nation on earth.
Explanation: A hyperbole is a type of figurative language that consists in exaggerating an event or a statement. In the given excerpt from "The American Promise" we can see a clear example of an hyperbole in the phrase "the Government of the greatest Nation on Earth" it is clearly an exaggeration, that isn't meant to be taken literally, but to convey a message and create an impact on the audience.
