The United States Constitution is the foundational legal document of the United States federal government, establishing the structure of government, enumerating and distributing powers among its branches, and setting limits on governmental authority over individuals. Ratified in 1788 and effective as of 4 March 1789, it replaced the Articles of Confederation as the supreme law of the land. The Constitution's meaning, proper interpretation, and application remain subjects of ongoing legal, political, and scholarly debate; contested questions include the scope of federal versus state power, the extent of individual rights, and the methods by which the document should be read.
The Constitution was drafted at the Philadelphia Convention in the summer of 1787 and subsequently ratified by the requisite nine of thirteen states by 21 June 1788. It consists of a Preamble, seven original Articles, and twenty-seven Amendments, the first ten of which - the Bill of Rights - were ratified together in 1791.
The original document established three branches of the federal government: a bicameral legislature (Congress), an executive (the President), and a federal judiciary (headed by the Supreme Court). It also included structural compromises among the states, including the Three-Fifths Compromise, which counted three-fifths of the enslaved population for purposes of congressional apportionment and taxation, and provisions protecting the international slave trade until 1808 and requiring the return of escaped enslaved persons across state lines. The relationship between these provisions and the Constitution's broader principles of liberty and equality has been a recurring subject of historical and legal controversy.
Constitutional interpretation is actively contested. Major interpretive schools include originalism, which holds that the document should be read according to its original public meaning or the framers' intent, and living constitutionalism, which holds that its meaning should evolve with changing circumstances. Courts, scholars, and practitioners continue to dispute how these frameworks apply to specific constitutional questions. For extended historical background, see us-constitution-history.
The Constitution has been amended twenty-seven times. The most transformative amendments are generally considered to be the Reconstruction Amendments (Thirteenth, Fourteenth, and Fifteenth), ratified between 1865 and 1870, which abolished slavery, established birthright citizenship and equal protection, and extended voting rights regardless of race.
There is broad scholarly consensus that the Constitution, as ratified in 1788, contained explicit protections for the institution of slavery, including the Three-Fifths Clause, the Slave Trade Clause, and the Fugitive Slave Clause, and that these provisions were material to securing ratification from slaveholding states. See us-constitution-slavery-provisions-consensus.1) There is also consensus that the Constitution, as subsequently amended, prohibits slavery and guarantees equal protection of the laws. Scholarly disagreement persists on questions of original intent, the degree to which the framers anticipated or sought to foreclose emancipation, and the correct method of constitutional interpretation.
Originalism holds that the Constitution should be interpreted according to the original public meaning of its text at the time of ratification, or in some variants, according to the framers' intent. Proponents argue this approach constrains judicial discretion and preserves democratic accountability. See us-constitution-originalism-viewpoint.
Living constitutionalism holds that the Constitution's meaning evolves with social and historical change, and that courts legitimately adapt its principles to new circumstances. Proponents argue this approach prevents the document from becoming obsolete. See us-constitution-living-constitutionalism-viewpoint.
Anti-federalist and states' rights perspectives hold that the Constitution, particularly as interpreted by the federal judiciary, has granted the federal government powers beyond those originally intended or enumerated, at the expense of state sovereignty and individual liberty. See us-constitution-anti-federalist-viewpoint.
Critical perspectives on the founding hold that the Constitution was designed in significant part to protect the interests of propertied and slaveholding elites, and that its structural features - including the Senate, the Electoral College, and the amendment process - entrench minority rule. See us-constitution-critical-founding-viewpoint.
Abolitionist and natural-law interpretations hold, or historically held, that the Constitution's principles of liberty and equality were incompatible with slavery, and that the document should be read as a fundamentally anti-slavery text. Figures such as Frederick Douglass advanced this view in contrast to those who read the Constitution as a pro-slavery compact. See us-constitution-abolitionist-interpretation-viewpoint.
Slavery and the founding compact: The extent to which the Constitution's framers deliberately protected slavery, and what moral and political weight that history carries for contemporary interpretation, is a documented and ongoing scholarly and public controversy. See us-constitution-slavery-founding-controversy.
Ratification and the anti-federalists: Opposition to ratification raised substantive objections - including concerns about the absence of a bill of rights, excessive central power, and risks to state sovereignty - that shaped both the final document and subsequent interpretation. See us-constitution-anti-federalist-ratification-controversy.
Judicial review and democratic legitimacy: The doctrine of judicial review, established by practice if not explicit text, has generated recurring controversy about the proper role of unelected courts in a democratic system. See us-constitution-judicial-review-controversy.
The Electoral College: The constitutional mechanism for presidential election has been the subject of sustained controversy regarding its democratic character, its origins in part in slavery-era apportionment, and proposals for its reform or abolition. See us-constitution-electoral-college-controversy.