Short answers, pulled from the story.
The colonies gathered in Philadelphia to ratify and adopt the Constitution on the 4th of March 1789. This document established the nation's federal rule of law and has been in continuous effect since that date.
The U.S. federal government is composed of three distinct branches: legislative, executive, and judicial. These powers are defined and vested by the U.S. Constitution.
The U.S. House of Representatives is made up of 435 voting members who represent congressional districts in each state. Apportionment of seats among the 50 states is determined by state populations and updated after each decennial U.S. Census.
The White House includes the office of the U.S. president known as the Oval Office and the offices of key presidential advisors and staff. The executive branch is established in Article Two of the United States Constitution which vests executive power in the president of the United States.
Residents of the District of Columbia have participated in presidential elections since the 29th of March 1961. They remain subject to federal laws and federal taxes while their only congressional representative serves as a non-voting delegate.