Preamble goals and what each article actually does.
The Preamble is the purpose statement
The Preamble begins “We the People,” which announces popular sovereignty: the government’s power comes from the people, not from a king or from the states alone.
It lists six goals: form a more perfect union (fix the Articles), establish justice (fair courts), insure domestic tranquility (peace at home), provide for the common defense (protect the country), promote the general welfare (help the community thrive), and secure the blessings of liberty for the writers and future generations (posterity).
Remember: The Preamble is goals, not a list of powers. Courts do not treat it as a source of new government powers.
Articles I, II, and III — the three branches
Article I creates Congress. It is the longest article because the Founders were most careful about the lawmaking branch. Section 8 lists many of Congress’s enumerated powers, including taxing, borrowing, regulating commerce with foreign nations and among the states, coining money, declaring war, and raising armies. The necessary and proper clause lets Congress pass laws needed to carry out those listed powers. That is the source of implied powers.
Article II creates the presidency. The president enforces laws, commands the military, makes treaties with Senate approval, appoints judges and officials, and can veto bills.
Article III creates the Supreme Court and lets Congress create lower federal courts. It does not spell out every detail of judicial review. That power was confirmed later in Marbury v. Madison (1803).
Articles IV through VII
Article IV covers the states: full faith and credit (states respect each other’s public acts and court decisions), privileges and immunities, and how new states join. It also guarantees each state a republican form of government.
Article V explains how to amend the Constitution. Article VI contains the supremacy clause: the Constitution, federal laws, and treaties are the supreme law of the land when they conflict with state law. It also bans religious tests for federal office. Article VII said nine states had to ratify before the Constitution took effect.
Remember: Supremacy clause = federal Constitution and valid federal law beat conflicting state law.