Government is the institution that makes and enforces rules, laws and policies. It is also the body that represents and defends a group of people or a region. Governments vary in their size and structure, but they all have the same basic function: to protect their citizens from external threats, internal conflicts and economic pressures. Governments may be democratic, authoritarian or a mix of elements from both types.

In a democratic government, the people make decisions through representatives elected by voters. In an authoritarian government, power is concentrated in the hands of a few people (often one political party or a single leader), and remains largely unchecked. Many countries combine features of democratic and authoritarian models, resulting in governments that limit some freedoms while protecting others.

Governments are necessary for civilized societies to function properly and protect their citizens. They provide stability and security in the form of a military, police forces and public education; social services such as health care, food and housing assistance for the poor; and essential utilities such as transportation, mail delivery and water treatment. Governments are also required to manage natural resources, such as fish in the sea and clean drinking water.

A key function of government is to collect taxes in order to pay for these vital services. The most common tax is a sales tax, which is collected by state and local governments to finance public services. Governments also collect income, payroll and property taxes in some jurisdictions.

Governments can be divided into three branches: the legislative, executive and judicial. The legislative branch enacts laws, while the executive branch enforces those laws. The judicial branch interprets and applies the law, and ensures that those laws are not in conflict with each other.

The executive branch of a country manages diplomatic relations with other countries, and signs agreements or negotiates with foreign governments. The President also carries out his duties as Commander-in-Chief of the armed forces. The President nominates Supreme Court and other federal judges, who are then confirmed by the Senate. The judicial branch interprets and applies laws, and hears cases in which a person is charged with a crime.

A governmental organization that coordinates the activities of associated government officials and candidates for office is called a political party. Many people in a society join political parties because they share similar ideas and philosophies of what role government should play. The political party system allows for more choices of government leaders and more competition for governmental positions.