Government is the organization through which a nation, state or other political unit exercises authority and enforces rules. Its responsibilities include the protection of its people, foreign policy and defense, economics, and public services. Its system of rule varies, from a direct democracy to a monarchy to a dictatorship.

The first duty of a government is to protect its citizens. This requires military strength, which is expensive and needs a large workforce of soldiers, engineers and support personnel. It also requires the governing body to develop a plan for attack or defense and then implement that plan. It must also be able to gather taxes and resources from citizens to pay for these expenses.

A second duty of a government is to provide other goods and services for its citizens. These might include schools, libraries, fire departments and police. In the United States, for example, the federal, state and local governments all provide these services. They raise money to pay for them by imposing taxes on income, property and sales. Governments also draft budgets to determine how to spend the money they raise.

Another important service provided by government is to ensure that there are sufficient supplies of some natural resources. For example, government regulates access to public lands and wildlife, which might otherwise be taken by individuals without regard for the rights of others. It is impossible for the free market to provide these kinds of resources in the quantity and at the low costs needed for all people to enjoy them. Governments can do this because they are able to tax and use the resources of a nation, and because they can compel citizen compliance with their laws and regulations.

Finally, governments may promote social and cultural values by setting enforceable rules and providing education. For example, western democracies like the United States, Britain and France promote freedom of speech and the press. They also limit the power of government officials and guarantee the rights of citizens. They encourage competition between rival political parties, which helps keep the power of government in check by providing a choice for voters.

The structure of a government may differ from one to the next, but all of them are organized into distinct institutions with different powers, functions, duties and responsibilities. These are known as branches of government, and they are typically organized into the executive, legislative and judicial branches. In the United States, for example, Congress creates legislation and passes judgments on legal cases. The president, who is an ex officio member of the executive branch, can veto legislation passed by Congress and nominate heads of government departments and high court appointees. This provides checks and balances and keeps the presidency from becoming too powerful.