why do all state constitutions have to be in agreement with the us constitution
State constitution (United States) The Tenth Amendment to the United States Constitution, part of the Bill of Rights, provides that "The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people." The Guarantee Clause of Article 4 of the Constitution states that "The United States shall guarantee to every State in this Union a Republican Form of Government." These two provisions indicate states did not surrender their wide latitude to adopt a constitution, the fundamental documents of state law, when the U.S. Constitution was adopted.
United States Constitution The preamble to the Constitution serves as an introductory statement of the document's fundamental purposes and guiding principles. It neither assigns powers to the federal government,[46] nor does it place specific limitations on government action. Rather, it sets out the origin, scope and purpose of the Constitution. Its origin and authority is in "We, the people of the United States". This echoes the Declaration of Independence. "One people" dissolved their connection with another, and assumed among the powers of the earth, a sovereign nation-state. The scope of the Constitution is twofold. First, "to form a more perfect Union" than had previously existed in the "perpetual Union" of the Articles of Confederation. Second, to "secure the blessings of liberty", which were to be enjoyed by not only the first generation, but for all who came after, "our posterity".[47]