Article Six of the United States Constitution in the context of "State constitutions in the United States"

The Constitution of the United States is the supreme law of the United States of America. It superseded the Articles of Confederation, the nation's first constitution, on March 4, 1789. Originally including seven articles, the Constitution defined the foundational structure of the federal government.

The drafting of the Constitution by many of the nation's Founding Fathers, often referred to as its framing, was completed at the Constitutional Convention, which assembled at Independence Hall in Philadelphia between May 25 and September 17, 1787. Influenced by English common law and the Enlightenment liberalism of philosophers like John Locke and Montesquieu, the Constitution's first three articles embody the doctrine of the separation of powers, in which the federal government is divided into the legislative, bicameral Congress; the executive, led by the president; and the judiciary, within which the Supreme Court has apex jurisdiction. Articles IV, V, and VI embody concepts of federalism, describing the rights and responsibilities of state governments, the states in relationship to the federal government, and the process of constitutional amendment. Article VII establishes the procedure used to ratify the constitution.

The Supremacy Clause of the Constitution of the United States (Article VI, Clause 2) establishes that the Constitution, federal laws made pursuant to it, and treaties made under the authority of the United States, constitute the "supreme Law of the Land", and thus take priority over any conflicting state laws. It provides that state courts are bound by, and state constitutions subordinate to, the supreme law. However, federal statutes and treaties must be within the parameters of the Constitution; that is, they must be pursuant to the federal government's enumerated powers, and not violate other constitutional limits on federal power, such as the Bill of Rights—of particular interest is the Tenth Amendment to the United States Constitution, which states that the federal government has only those powers that are delegated to it by the Constitution. It is the responsibility of the United States Supreme Court in that case to exercise the power of judicial review: the ability to invalidate a statute for violating a provision of the Constitution.

The Supremacy Clause is essentially a conflict-of-laws rule specifying that certain federal acts take priority over any state acts that conflict with federal law. Some jurists further argue that the clause also nullifies federal law that is in conflict with the Constitution, although this is disputed. The Supremacy Clause follows Article XIII of the Articles of Confederation, the predecessor of the Constitution, which provided that "Every State shall abide by the determination of the [Congress], on all questions which by this confederation are submitted to them."

In the United States of America, each state has its own written constitution. The Supremacy Clause of the Constitution of the United States (Article VI, Clause 2) establishes that the Constitution, federal laws made pursuant to it, and treaties made under the authority of the United States, constitute the "supreme Law of the Land", and thus take priority over any conflicting state laws. It provides that state courts are bound by, and state constitutions subordinate to, the supreme law.

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.

The oath of office of the president of the United States is the oath or affirmation that the president of the United States takes upon assuming office. The wording of the oath is specified in Article II, Section One, Clause 8, of the United States Constitution, and a new president is required to take it before exercising or carrying out any official powers or duties.

This clause is one of three oath or affirmation clauses in the Constitution, but it is the only one that actually specifies the words that must be spoken. Article I, Section 3 requires Senators, when sitting to try impeachments, to be "on Oath or Affirmation." Article VI, Clause 3, similarly requires the persons specified therein to "be bound by oath or affirmation, to support this Constitution." The presidential oath requires much more than that general oath of allegiance and fidelity. This clause enjoins the new president to swear or affirm: "I will to the best of my ability, preserve, protect and defend the Constitution of the United States."

In the United States, judicial review is the legal power of a court to determine if a statute, treaty, or administrative regulation contradicts or violates the provisions of existing law, a state constitution, or ultimately the United States Constitution. While the U.S. Constitution does not explicitly define the power of judicial review, the authority for judicial review in the United States has been inferred from the structure, provisions, and history of the Constitution.

Two landmark decisions by the U.S. Supreme Court served to confirm the inferred constitutional authority for judicial review in the United States. In 1796, Hylton v. United States was the first case decided by the Supreme Court involving a direct challenge to the constitutionality of an act of Congress, the Carriage Act of 1794 which imposed a "carriage tax". The Court performed judicial review of the plaintiff's claim that the carriage tax was unconstitutional. After review, the Supreme Court decided the Carriage Act was constitutional. In 1803, Marbury v. Madison was the first Supreme Court case where the Court asserted its authority to strike down a law as unconstitutional. At the end of his opinion in this decision, Chief Justice John Marshall maintained that the Supreme Court's responsibility to overturn unconstitutional legislation was a necessary consequence of their sworn oath of office to uphold the Constitution as instructed in Article Six of the Constitution.