| 1620 | Pilgrims sign the Mayflower Compact |
| 1776 | Second Continental Congress authorizes colonies to create republican government (May), Eight states draft new constitutions; two others already enjoy republican government by virtue of former colonial charters |
| 1777 | Congress accepts Articles of Confederation after long debate (November) |
| 1780 | Massachusetts finally ratifies state constitution |
| 1781 | States ratify Articles of Confederation following settlement of Virginia’s western land claims |
| 1786 | Annapolis Convention suggests second meeting to revise the Articles of Confederation (September) |
| 1787-1788 | The federal Constitution is ratified by all states except North Carolina and Rhode Island |
| 1789 | Virginia and Kentucky Resolutions protest the Alien and Sedition Acts (November and December) |
| 1791 | Bill of Rights (first ten amendments of the Constitution) ratified by states |
| 1802 | Judiciary Act is repealed (March) |
| 1803 | Chief Justice John Marshall rules on Marbury v. Madison (February), setting precedent for judicial review |
| 1814 | Hartford Convention meets to recommend constitutional changes (December) |
| 1819 | Supreme Court hands down far-reaching decision in Dartmouth College case and in McCulloch v. Maryland |
| 1824 | Supreme Court decides Gibbons v. Ogden |
| 1832-1833 | Crisis erupts over South Carolina's attempt to nullify the tariff of 1832 |
| 1857 | Supreme Court decides Dred Scott case and legalizes slavery in all territories |
| 1860 | South Carolina secedes from the Union (December) |
| 1861 | Rest of Deep South secedes: Confederacy is founded (January-February) |
| 1861 | Upper South secedes (April-May) |
| 1866 | Congress passes Fourteenth Amendment (June) |
| 1896 | Supreme Court decision in Plessy v. Ferguson establishes constitutionality of "separate but equal" facilities |
| 1918 | Supreme Court strikes down federal law limiting child labor in Hammer v. Dagenhart |
| 1920 | Nineteenth Amendment gives women the right to vote |
| 1933 | Twenty-first Amendment repeals Prohibition (December) |
| 1937 | FDR loses court-packing battle (July) |
| 1954 | Supreme Court orders schools desegregated in Brown v. Board of Education of Topeka (May) |
| 1971 | States ratify 26th Amendment to the Constitution, giving 18-year-olds the right to vote (July) |