Government makes rules about how people should behave in a nation or community, and it administers those laws. It also provides some goods and services that are not easily provided by the market—for example, national security, education, public transportation, and health care for all citizens. Some citizens may disagree with the goals or actions of a particular government, but they usually must work within that system to shape its policy and make it better.

How a government governs is an important topic of study, and many types have been created through the centuries. But all governments have one important thing in common: they create rules. Governments also set the stage for citizen behavior and protect citizens from outside interference or invasion.

In the United States, our government has three major branches, each of which has its own responsibilities. The first is Congress, which includes the House of Representatives and Senate. Each state gets a certain number of representatives, and every 10 years we adjust that number to reflect the changing population. The House and Senate both vote on laws, and a law needs the support of a majority of members in order to pass.

The next branch is the Executive Branch, which carries out and enforces the laws passed by Congress. This branch has the President and Cabinet, which have big responsibilities. The President is the head of the Executive Branch and our Head of State, and he or she negotiates with leaders in other countries. The third branch is the Judicial Branch, which judges cases and makes sure that laws are applied correctly. This branch also appoints and confirms Supreme Court justices, who can overturn unconstitutional laws.

Most Americans believe that their government is doing a good job. They are less confident about the quality of the medical system, however, and less likely to feel safe in public places. These are just two of the findings of a new study by the Pew Research Center, which finds that Americans’ views about their own country have changed over time.

One reason for these changes is that our government has evolved over the years. The Constitution lays out some basic rules, and years of building upon those rules have resulted in the multi-leveled system we know today. But it’s not easy to identify the characteristics of a specific form of government. Some political scientists are working on ways to classify governmental systems. Some of the traits that these scholars look for include: Majority rule with minority rights; accountability; limited government; a Bill of Rights; economic freedom; and checks and balances.