Government is the institution through which a political unit, such as a nation or state, exercises authority and performs functions. Government is the entity that allocates funds at the local, city, town, county, state, and federal levels for things such as military defense, maintenance of roads and bridges, management of national parks, and education. Government also helps to protect public goods, things that everybody can use, but that are in limited supply, such as clean water and fish in the sea.

Government has evolved as a response to the many needs and problems that humans face in their daily lives. Humans require a stable environment in which to live and to work, and they need food, shelter, and medical care. Governments at all levels provide these basic necessities, among others, by providing security in the form of a police force and fire department. Governments also make sure that people have a means of transportation and that they receive the mail. Governments can also provide a variety of services for the poor, such as free meals and housing.

A key function of government is the protection of citizens from aggression, violence, natural disasters, and poverty and discrimination. Governments at all levels have the duty to protect their constituents, and they can do this by imposing rules and regulations that set limits on what people can do and by enforcing those limits when they are violated.

In addition to protecting their citizens, governments regulate private commerce in order to keep the economy running smoothly and to ensure that all of the money being spent is being well spent. This can be done by requiring that certain goods and services be produced only by businesses that have a license to do so or by banning products like DDT, a compound used to kill insects, and PCBs, a group of compounds used as cooling fluids in electrical devices.

Governments raise the funds to pay for their various programs by collecting taxes and fees and borrowing money from the public in the form of bonds. Governments may also receive some of the money they need from private businesses by entering into contracts with them.

The structure of a government differs from one country and state to the next, but they all share the same fundamental function: to lead and protect their citizens. In democracies, citizens decide the direction of their government through the voting process by electing representatives to govern on their behalf. In authoritarian countries, power is concentrated in the hands of a few individuals or in one political party and remains largely unchecked. In most modern nations, however, governments are a mixture of democratic and authoritarian elements, and they balance the competing needs of liberty and security.

Aside from regulating the economy, governments are responsible for providing services that individuals cannot effectively produce on their own, such as military defense, fire and police departments, roads, and education. Governments at all levels are required to allocate money for these and other priorities by deciding how much of the public’s tax dollars should go to each purpose.