Here is a 3 paragraph, 453-word essay on the purpose of government:
The primary purpose of any government is to protect the basic rights and freedoms of its citizens. A key function of government is to establish and enforce laws that maintain order, security, and justice. Without an organized system of rules and consequences, society breaks down as individuals only act in their own self-interest without regard for others. It is the role of government to create a structured legal system that balances the rights of individuals with the needs of the broader community.
Within the United States, the federal government is composed of three separate but co-equal branches that check and balance each other: the legislative, executive, and judicial branches. This separation of