Government is a system of rules and responsibilities for a nation, state or other political unit. The duties of a government include the defense and protection of citizens, foreign affairs, economics and public services. Governments may take many forms, including a direct democracy, a representative democracy, socialism, communism, a monarchy or an autocracy.

Generally, governments are made up of three distinct institutions: the legislative branch (consisted of the House of Representatives and the Senate), the executive branch, and the judicial branch. Combined, these branches create, enforce and interpret national laws. The Constitution established this check-and-balances system, with each branch providing oversight to the other and preventing abuses of power.

While most contemporary political thinkers agree that government should be limited, there is significant disagreement over what those limits should be. Some believe that the role of government should be to solve problems that cannot be solved by market forces alone, such as environmental pollution. For example, if it is impossible for individual victims of pollution to sue polluting industries in court, the solution might be to penalize those industries via federal legislation and regulation.

Other people argue that the role of government should be to protect citizens from violence and provide basic necessities like food, water and shelter. To accomplish these tasks, government must raise taxes and employ people to run its services and departments. This employment often provides better benefits than jobs in the private sector, and offers job security. Government workers can also retire with a pension and retiree health care plan.

Another function of government is to regulate the use and access of common goods like land, wildlife and natural resources. This is important because these resources are in limited supply and, if they are used too freely by certain people, will disappear altogether. Governments must therefore control the use of these resources in order to ensure that they are available to everyone.

Governments need a stable and reliable source of funding to perform their functions and serve the public. To raise funds, they collect taxes from their citizens, which are then used to pay for police and fire protection, schools, roads, and social services. Governments can also make investments that can help increase the prosperity of their citizens and reduce the number of people living in poverty, such as public works projects and research into new medical treatments. Governments can also control the flow of money within a country, by setting interest rates and creating monetary policies. These policies can be used to stabilize the economy and reduce inflation. They can also be used to stimulate the economy by increasing spending on public programs like education, health and housing for the elderly. Governments can also make decisions about military spending, and even declare war.