Question

What is
A government in power?

Answer 1

The federal government is composed of three distinct branches: legislative, executive, and judicial, whose powers are vested by the U.S. Constitution in the Congress, the president and the federal courts, respectively.
...
Federal government of the United States.

Answer 2

Powers are vested in Congress, in the President, and the federal courts by the United States Constitution. ... It is based on the principle of federalism, where power is shared between the federal government and state governments. The powers of the federal government have generally expanded greatly since the Civil War.