The Fifth Amendment protects citizens from government overreach in several ways: it ensures people cannot be prosecuted for a major crime without evidence presented to a grand jury, prevents people from being tried twice for the same crime, and protects individuals from being forced to testify against themselves or have their property taken without compensation. It codifies principles like due process and the presumption of innocence to ensure legal proceedings are fair. The amendment was included in the Constitution to safeguard individual rights and reign in government power over citizens.