The government creates rules that govern a nation, state, or other political unit. It also has responsibilities for protecting citizens and regulating the economy. But how governments perform those functions varies widely. What’s important is that every society needs a system of order—and that means government.

Governments have a variety of roles in the economy, including protecting goods that are available to everyone but are of limited supply, like fish in the sea or clean drinking water; providing national defense; addressing environmental concerns; and defining and protecting property rights. They also redistribute income through taxes and borrowing. The aims of government in the economy are often defined by a philosophy called functionalism, which believes that a society develops social structures and institutions that persist because they serve a valuable function. This is a key idea in public policy.

In a democracy, citizens make decisions about what kinds of government they need and want. They choose leaders through a voting process and elect them to represent them in the legislature, which passes laws and oversees the executive branch. They also decide how to fund government and what kind of services it should provide.

People generally agree that the government should do some things, such as protecting against terrorism and natural disasters, ensuring safe food and medicine, strengthening the economy, and providing for education and social welfare. But there are differences among partisans on what is the right size and scope of government.

The most common form of government is a democracy, which involves the direct or indirect participation of citizens in making decisions about how to run a society. But there are many other ways to organize a political community, including a republic, a constitutional monarchy, a socialist state, or an autocracy.

Each type of government has a different approach to the role that government should play in the economy. Some are more concerned with efficiency and others are more focused on achieving particular ideals, such as egalitarianism or reducing socioeconomic inequalities.

Regardless of what kind of government is in place, one key to its success is a spirit of mutual toleration. This includes the willingness to accept the ideas of political opponents, even if you disagree with them strongly. It also means not using the power of government to hurt people who aren’t part of your political party.

A government’s powers are limited by the Constitution and other laws. Those limits are enforced by the judicial, legislative, and executive branches of the government. Each of these branches has its own unique responsibilities, as shown in the infographic below. For example, the President can veto legislation passed by Congress or nominate judges to the Supreme Court and other federal courts. Congress, in turn, can confirm or reject those nominees and impeach the President if necessary. This is known as the system of checks and balances.