Every major event that built, tested, or reshaped the three branches — filter by branch or search by keyword.
Delegates from 12 colonies meet in Philadelphia to coordinate resistance to Britain's Coercive Acts — the first shared American governing body.
The Second Continental Congress adopts the Declaration on July 4. It governs the new states alone — no separate executive, no national courts.
A "firm league of friendship" with a single Congress, no power to tax, and no way to enforce its own laws on the states.
An armed uprising of Massachusetts farmers that the Confederation government cannot suppress — proof to many leaders that the union needed a stronger center.
55 delegates meet in Philadelphia, May–September. The Great Compromise creates a bicameral Congress; the finished Constitution is signed September 17.
New Hampshire becomes the 9th state to ratify on June 21, making the new government operative.
First Congress meets March 4; Washington is inaugurated April 30; the Judiciary Act of 1789 creates the federal court system.
The first 10 amendments take effect December 15, drafted by Madison in the First Congress.
Declines a third term and warns against permanent foreign alliances and political factions — shaping American politics for a century.
Jefferson defeats Adams — the first peaceful transfer of power between rival parties anywhere in the modern world.
The Court establishes judicial review — the power to strike down laws that conflict with the Constitution.
Doubles the nation's size; Jefferson pushes it through despite his own doubts about its constitutionality.
Upholds broad federal implied powers and supremacy over the states.
Speaker Henry Clay engineers a deal managing slavery's expansion into new territories.
Blocks the re-charter of the Second Bank of the United States, asserting the President's own constitutional judgment against the Court's.
Denies Black Americans citizenship and strikes down the Missouri Compromise — deepening the crisis that led to civil war.
Lincoln suspends habeas corpus and expands executive war powers without waiting for Congress.
Declares enslaved people in Confederate territory free — issued as a wartime executive order.
Slavery abolished nationwide in December; Lincoln shot in April, days after Confederate surrender.
First presidential impeachment — the Senate acquits by a single vote. The 14th Amendment guarantees citizenship and equal protection.
The Judiciary Act of 1869 sets the Court's size where it remains today.
Bars denying the vote on the basis of race.
Killed by a disappointed office-seeker; Congress responds with the Pendleton Civil Service Act, ending most political patronage hiring.
Upholds "separate but equal" racial segregation — overturned nearly six decades later.
Becomes president after McKinley's assassination; expands the regulatory reach of the executive branch.
Federal income tax authorized; senators now elected directly by voters instead of state legislatures.
Congress grants Wilson sweeping wartime powers over the economy and speech.
Guarantees women's suffrage nationwide.
The Reapportionment Act permanently caps the House, ending a century of growth alongside the population.
FDR's first "Hundred Days" dramatically expand the executive's regulatory and economic role.
Schechter Poultry and Butler v. United States rule key New Deal programs unconstitutional.
FDR's plan to add up to 6 justices fails in Congress — but the Court's rulings shift toward the New Deal soon after.
Congress declares war on Japan within a day of the attack.
Upholds Japanese-American internment — later repudiated by the government (1988) and the Court itself (2018).
Becomes president on FDR's death in April; orders the bombs that end WWII in August.
Limits presidents to two elected terms, codifying Washington's voluntary precedent.
Unanimously ends legal school segregation, overturning Plessy.
Passed with bipartisan coalitions and pushed hard by President Johnson.
Clarifies presidential succession and disability; Thurgood Marshall joins the Supreme Court.
The Court finds a constitutional right to abortion; Congress, over Nixon's veto, reasserts control over military deployments.
United States v. Nixon forces the tapes' release; Nixon resigns August 9 — still the only presidential resignation. Congress passes the Budget and Impoundment Control Act.
Sandra Day O'Connor joins the Supreme Court.
Tests the limits of executive power and Congress's oversight of covert action.
Fought under a congressional use-of-force authorization rather than a formal declaration of war.
Second presidential impeachment, over perjury and obstruction; the Senate acquits in 1999.
Halts the Florida recount and decides the presidential election — one of the Court's most debated rulings.
Congress authorizes military force and passes sweeping new surveillance powers within weeks of the attacks.
The largest reorganization of the federal government since 1947.
The Court reshapes campaign finance law; Congress passes the Affordable Care Act, upheld by the Court in 2012.
Strikes down the Voting Rights Act's preclearance coverage formula.
Legalizes same-sex marriage nationwide.
December 2019 (abuse of power, obstruction of Congress) and January 2021 (incitement of insurrection); the Senate acquits both times.
Overturns Roe and Casey, returning abortion regulation to the states.
Second in U.S. history, after Grover Cleveland, to serve non-consecutive terms.
The Court rules the emergency-powers law Trump used to impose global tariffs didn't authorize it — Congress, not the president, holds the tariff power.
Narrows the Voting Rights Act's limits on race-based redistricting, prompting several states to redraw congressional maps ahead of the 2026 midterms.
Reaffirms the 14th Amendment's guarantee of birthright citizenship, rejecting an executive order that sought to narrow it.