Legislation is the process by which laws are created or changed by a governing body like a parliament. The constitution is a country's fundamental law that outlines the principles and structures of government, defines citizen rights and freedoms, and establishes rules for decision making. Many constitutions establish the legislative process and bodies like the US Congress. Constitutional amendments may be needed to change the legislative process or laws and require high approval thresholds like supermajority votes or referendums. Overall, legislation enforces the principles in the constitution.