What is an amendment?

An amendment refers specifically to a formal change or addition to the Constitution. The U.S. Constitution can be altered through these amendments, which allow for adaptation to evolving societal values and issues. This process is crucial because it enables the Constitution to remain relevant and responsive to the needs of the nation over time.

The significance of amendments is underscored by the fact that they can alter the legal framework and rights of citizens, as seen in various historical amendments that expanded civil rights and liberties. This includes the Bill of Rights, which comprises the first ten amendments, specifically designed to protect individual freedoms and limit government power.

The other answer choices relate to different concepts. A declaration of war pertains to formal announcements made by Congress about military engagement, while a law passed by Congress is a legislative measure that must go through a specific process of drafting, debate, and voting. A preamble, on the other hand, serves as an introduction to the Constitution, outlining its purposes and guiding principles, but it does not constitute a formal alteration or addition to the Constitution itself. Thus, the correct answer reflects the essential function of an amendment in the context of constitutional law.