The United States of America is a federal republic consisting of 50 states. Each of which has its own government ("state government"). In some ways the United States is like 50 small countries. Each state has its own governor, its own police and its own laws. The present constitution was proclaimed in 1787 in Philadelphia, the President is the head of the whole country and the government and "commander-in-chief" of the armed forces. He makes the most important decisions and chooses the ministers, the members of his cabinet. But the President cannot do just what he wants. The Congress must agree first. The Americans choose a new president every four years. The residence of the President is the White House in Washington, the Capital city.
The government of the whole country (the Federal government) works from Washington; this is where the Congress is based. The Capitol is the seat of the US Congress. Congress is the American parliament which consists of 2 chambers. The Senate and the House of Representatives. The first Congress met in 1789 in New York city. The membership then consisted of 22 senators and 59 representatives. Today the House of Representatives has 435 members. Elections to the house take place every 2 years. There are 100 senators (2 from each state), they are elected to serve for a period of six years, but every two years elections to the senate took place when one-third of its members must be changed or re-elected. Election day is always in the month of November, on the first Tuesday, after the first Monday. Americans who aren't yet 25 years old have no right to be elected to the House of Representatives. Those who are under 30 can't be elected in the Senate. The main political parties in the United States of America are the Democratic Party and the Republican Party.