The Prize Cases established that the president can respond to an attack without waiting for Congress to act

In the midst of the Civil War, Lincoln rapidly expanded presidential power

Abraham Lincoln suspended habeas corpus, expanded the army without congressional approval, and issued the Emancipation Proclamation—despite likely lacking authority to unilaterally alter national slave law. His actions set precedents for expanded presidential power in wartime.

The Barbary Wars were an early test of whether a president could wage war without a formal declaration from Congress

Jefferson sent naval forces against North African pirates without a congressional declaration of war, acting under his own authority. Years later, Madison took the opposite approach and formally sought congressional authorization.

Presidents have often used military force without formal declarations of war

Although the Constitution grants Congress the power to declare war, American presidents have repeatedly ordered military action without formal declarations. These precedents have expanded executive authority in national security beyond what the framers likely envisioned.

The first test of America's war powers came just a decade after the Constitution was ratified

During the undeclared Quasi-War with France in 1800, the Supreme Court ruled in Bas v. Tingy that Congress had authorized a valid "imperfect war" through statutes alone, without a formal declaration, establishing that there is a legal spectrum between peace and declared war.

The president can deploy the military domestically with minimal oversight

The Insurrection Act of 1807 allows the president to send federal troops into American states during unrest or rebellion, even without a governor's consent. The modern use of the law grants broad discretion and limited congressional or judicial oversight.

Presidents from both parties have resisted the authority of the War Powers Act

Presidents from both parties have treated the War Powers Resolution as voluntary, framing compliance as seeking "support" rather than "permission." Courts have declined to rule on the law's constitutionality each time a related case was brought before them.

In his 1859 annual message to Congress, President Buchanan articulated a narrow view of presidential military authority

Buchanan argued that the president lacked constitutional authority to launch offensive military action without congressional approval, a view that reflected the prevailing interpretation of executive war powers throughout much of the nineteenth century.

Future President Abraham Lincoln challenged Polk’s justification for war with Mexico

As a freshman congressman, Abraham Lincoln introduced the “Spot Resolutions,” demanding President Polk prove that Mexico had attacked on US soil. This constituted Lincoln’s first major political stand and highlighted growing dissent over the war.

Abraham Lincoln's victory in 1860 sparked Southern secession—even before his inauguration

Abraham Lincoln's election on an antislavery expansion platform convinced many Southerners that their way of life was under threat. Within three months, seven states seceded from the Union—forming the Confederacy—before Lincoln took office in March 1861.

A legal scholar argues that the existing war powers framework may collapse in the event of a major power conflict

The legal tests presidents have used to avoid seeking congressional authorization were designed for weaker adversaries. This piece argues that those tests fail against similarly armed competitors, where even limited strikes risk significant escalation, potentially triggering a constitutional crisis over who has the authority to respond.

Youngstown Sheet & Tube Co. v. Sawyer established the framework courts use to evaluate presidential war powers

When Truman seized US steel mills during the Korean War, the Supreme Court ruled that he had overstepped his authority. Justice Jackson's concurring opinion held that presidential power is strongest when Congress authorizes action, uncertain when Congress is silent, and weakest when Congress explicitly refuses authorization.

The president has the sole authority to call for a nuclear strike

Under current US policy, the president alone can order the use of atomic weapons at any time without requiring prior approval from Congress—a power rooted in the president's role as commander in chief.

Truman's decision to enter the Korean War without congressional authorization marked a major shift in presidential war powers

Rather than seeking a declaration of war, Truman sent troops to Korea under his own authority, citing the UN Charter and his role as commander in chief. The decision set a precedent that subsequent presidents have relied on ever since.

The Supreme Court ruled in February 2026 that Trump's emergency tariff powers didn't extend to imposing tariffs

In a 6-3 decision, the court held that the International Emergency Economic Powers Act—a 1977 law granting the president authority to regulate commerce during national emergencies—does not authorise the president to unilaterally impose tariffs, a power the Constitution reserves to Congress.

Congress has handled past crises through emergency lawmaking and institutional expansion

In a 2020 podcast from the National Constitution Center, historians and political scientists examine how Congress navigated past national crises—particularly the Civil War—and what those moments reveal about governing today.

Ulysses S. Grant's leadership proved decisive in victory—and shaped postwar America

Elevated to general-in-chief in 1864, Ulysses S. Grant unified the Union strategy and forced a Confederate surrender at Appomattox. Elected president in 1868, he worked to enforce Reconstruction laws and protect the civil rights of freed African Americans.

Abraham Lincoln was almost assassinated weeks before his inauguration as he traveled from Illinois to DC through Baltimore in 1861; it took two independent claims for Lincoln to be convinced the threat was real

The nullification crisis tested whether states could defy federal law

In the 1830s, South Carolina declared federal tariffs void within its borders. President Andrew Jackson threatened military force, Congress passed a compromise tariff, and the episode ended with federal authority prevailing over state nullification.

The attack on Fort Sumter was the Civil War's first battle

Confederate forces fired on Union-held Fort Sumter in Charleston Harbor on April 12, 1861, after Lincoln refused to surrender it. The bombardment lasted 34 hours, forcing a Union surrender and marking the beginning of the Civil War.

John Marshall strengthened the Supreme Court and national authority

As chief justice, John Marshall established the principle of judicial review. He reinforced federal supremacy in key cases, defining the Supreme Court as a powerful arbiter between states and the national government under the US federal system.

Should the US have entered into World War I?

America entered World War I in 1917, but had remained neutral until that point. President Woodrow Wilson addressed Congress, further underlining the USA's neutrality. Eleven weeks later, he asked for a declaration of war. With attacks by German saboteurs on an American munitions depot, it seemed he had no choice. But did he? This article asks what might have happened if the US stayed out of WWI.

The Dred Scott decision denied citizenship to people of African descent

In 1857, the Supreme Court ruled in Dred Scott v. Sandford that Black Americans could not be US citizens. The decision heightened an already brewing conflict and became a key factor in pushing the nation toward civil war.

The attacks prompted a quick jump in American public support for war

In a Gallup poll taken days after the attack, an extraordinary 97% of Americans approved Congress declaring war on Japan—reflecting overwhelming national unity in the wake of the strike.

Brandenburg v. Ohio set the modern standard for when speech can be punished as incitement

A Ku Klux Klan leader's conviction for a threatening speech prompted the Supreme Court in 1969 to rule that speech is punishable as incitement only if it is directed at—and likely to produce—imminent lawless action.

The Senate must approve top presidential appointments

Under Article II of the Constitution, the United States Senate provides "advice and consent" on presidential nominees. This resource displays the outcome of every Cabinet nomination since Jimmy Carter's presidency and every Supreme Court nomination in US history.

Reactions inside the House chamber during the State of the Union are highly choreographed

Applause, silence, and coordinated standing—or refusal to stand—are deliberate signals during the State of the Union, used by lawmakers to broadcast allegiance or dissent. At the same time, military leaders and Supreme Court justices largely avoid reacting to preserve institutional neutrality.

The rivalry between Alexander Hamilton and Thomas Jefferson centered on federalism—the question of how much power the federal government should hold relative to the states.

Despite being favored by 87% of Americans, Congress does not have term limits.

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

Explore an interactive map of battles from the American Revolution, along with detailed summaries of each engagement

The idea for the Federal Reserve was conceived in secret in 1910—with bankers donning duck hunt gear for disguise while traveling to a remote country club on Georgia's Jekyll Island

In 2025, four executives from large tech companies were given positions in the US Army Reserves—including Palantir Chief Technology Officer Shyam Sankar, which reinforced Palantir's ties with the US military and its role as a leading defense partner.

The story of Dollree Mapp, whose legal challenge over her 1957 conviction for possessing "obscene material" led to a major strengthening of the Fourth Amendment

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

Mark Twain spent decades feuding with the US Postal Service, convinced its costs and regulations were bureaucratic overreach.

'Grand Canyon of the Yellowstone,' a work by American painter Thomas Moran, inspired Congress to establish Yellowstone National Park.

See this overview of the firework rules across all 50 states, ranging from a complete ban on non-professional fireworks in Massachusetts to states with more lax rules like Indiana.

Many legends about George Washington, including his supposed wooden teeth and the story of cutting down the cherry tree, lack evidence.

In 1984, Operation Smash Hit intentionally crashed a 239-ton train into a nuclear waste canister at 100 miles per hour to prove the canister's safety, which remained completely intact and lost just 0.29 of its 100 pounds of pressure.

The American Society of Civil Engineers' infrastructure report card gave the US a C in 2025, its highest grade since the project launched in 1998.

Warren Buffett's former professor Benjamin Graham is known as the 'father of value investing,' a strategy in which investors seek to buy stocks trading below their intrinsic worth.

Brandi Chastain, the star of the 1999 US victory over China in the 1999 Women's World Cup, was a last-second choice to take the penalty kick that sealed the victory.

Poison ivy's characteristic rash is caused by an allergic response to an oily compound in the plant called urushiol.

When caught in the mouths of cardinal fish, seed shrimp release glowing, bioluminescent chemicals, which alert predators of the cardinal fish, prompting the shrimp's ejection.

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

Learn how monoclonal antibodies, which mimic the body's antibodies, can fight diseases like Ebola.

Hurricanes, which rely on air consistently spinning in the same direction, cannot cross the equator because air curves in opposite directions north and south of it.

Sears sold DIY house kits starting at $600 in its famous catalog from 1908 through the 1940s, resulting in roughly 10,000 'Sears and Roebuck houses' being built.

English mathematician Ada Lovelace wrote the first computer algorithm a century before computers existed and hypothesized that computing devices would one day be able to compose music—foreseeing the generative AI systems of today.