Government is the body, entity or active agency invested with the power to manage a State or other political unit such as a country, a corporation or a community. Government can take many forms: monarchy, oligarchy, democracy (direct and indirect) and autocracy are some of them.
In the United States, the framers of the Constitution established three separate but equal branches of Government: The legislative branch (makes the law), the executive branch (enforces the law) and the judicial branch (interprets the laws). This system of checks and balances prevents any one branch from becoming too powerful or controlling all the resources of the Nation.
The legislative branch (the House of Representatives and the Senate) passes bills that become Public Laws when approved by Congress and signed by the President. The executive branch (the president and the cabinet) executes those laws. The judicial branch (the Supreme Court and federal courts) hears and makes decisions on legal cases brought before them. There are also a number of independent agencies, such as the US Postal Service, NASA and the Central Intelligence Agency, that are run by the Federal Government.
Most of these agencies provide goods and services that the private market cannot supply (either in sufficient quantity or at reasonable cost) — these are called public goods. The ability to collect taxes and compel citizen compliance allows Government to deliver these public goods. The other important function of Government is to protect the citizens of the nation. This is a very difficult task, and there are many different ways that Government can achieve this goal, including police forces, military forces, intelligence agencies, and national defense.