The Civil War permanently strengthened federal power

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.

Bills passed during the Civil War shaped postwar America

Despite the war with the South, Congress passed transformative laws like the Homestead Act and the Morrill Land-Grant College Act, which encouraged westward settlement and expanded higher education.

The Civil War introduced many technological advances to both society and warfare

The conflict accelerated innovations—including railroads, telegraphs, ironclad ships, and mass-produced weapons—while advances in photography, medicine, and manufacturing transformed how Americans communicated, healed, and built after the 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.

The South was placed under federal military rule during Reconstruction

Beginning in 1867, the Reconstruction Acts divided 10 former Confederate states into five military districts, each governed by a Union general. Federal troops supervised elections, enforced civil rights, and maintained order under direct congressional authority.

US westward expansion—and the status of slavery in the new territories—was a major cause of the American Civil War

The addition of new western lands forced the nation to confront whether slavery would spread beyond the South. Each debate over the admission of a new state sharpened the divide between free and slaveholding regions.

The Civil Rights Act expanded the Department of Justice's enforcement powers

The 1964 bill empowered the DOJ's Civil Rights Division to challenge segregation, protect voting rights, and prosecute discrimination, thereby expanding its role in defending civil rights.

The debate over federalism helped produce the novel character of the United States

During ratification, Federalists argued that a strong national government was essential for national survival. Anti-Federalists warned that it could overwhelm states and threaten individual liberty—forcing compromises that shaped early American federalism and led to the adoption of the Bill of Rights.

The Supreme Court has never definitively settled federal war powers

Despite more than two centuries of conflict over war powers, the Supreme Court has consistently avoided defining the precise boundary between congressional and executive authority, leaving that boundary to be contested by the political branches.

The New Deal shifted economic and social authority to the federal government

Franklin D. Roosevelt's response to the Great Depression expanded federal power through economic regulation and social welfare programs, permanently reshaping federalism by shifting responsibility for financial security to Washington while leaving states to administer many of these programs.

The Civil War turned the Continental Divide into an American symbol of identity

Historians argue that the boundary only became a celebrated American symbol in the 1860s, when Civil War-era leaders promoted a west-east geographic divide to replace the devastating north-south political divide, and that the term's use spiked after the transcontinental railroad crossed it in 1868.

Was the Civil War really about states' rights?

The Civil War was fought over slavery, and Confederate leaders and supporters admitted as much in the build-up to the war and after. But later on, after the South's defeat, the lie of the Lost Cause was pushed—and it persists to this day. This four-minute video details the story of the Lost Cause, "state's rights", Confederate monuments, and the machinations behind them.

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.

The power and influence of the American presidency have expanded significantly over time—far beyond what the founders envisioned.

The Civil War lasted for 4 years, with fighting taking place in a majority of the country

Fought from 1861 to 1865, the Civil War saw battles and raids across much of the country—from Pennsylvania to Texas and New Mexico to Florida.

The power and influence of the American presidency have expanded significantly over time—far beyond what the founders envisioned.

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.

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 13th Amendment permanently abolished slavery in the United States

Ratified in December 1865, the 13th Amendment outlawed slavery nationwide except as punishment for a crime. Southern states were required to ratify it under President Andrew Johnson's initial Reconstruction plan before regaining representation, though Congress later imposed stricter conditions.

The president can federalize state National Guard units during national emergencies

While the governor usually commands their state's National Guard, the president can assume control—federalizing the guard—under laws like the Insurrection Act or Title 10. Once federalized, troops operate under the US military chain of command.

The 10th Amendment affirms that most undelegated powers remain with the states

Adopted to reassure skeptics of an overly powerful federal government, the amendment was meant to curb federal overreach and preserve state control over most everyday governance decisions.

The commerce clause gives the federal government authority to regulate interstate economic activity

This short constitutional provision has allowed Congress to regulate everything from wheat production to racial segregation, greatly expanding federal power by linking national authority to interstate economic activity.

The Panama Canal boosted the US as a world power in trade, engineering, and finance

The effort proved the US could achieve grand engineering projects while granting it influence over (and benefitting economically from) a major interoceanic channel and its host country, Panama.

At the 1787 Constitutional Convention, Madison changed the draft language from Congress's power to "make" war to "declare" war

The change was deliberate: "make" war seemed to leave the president unable to defend the country against sudden attack, while "declare" preserved that defensive authority. The distinction between starting a war and responding to one has been debated ever since.

The United States is one of only around two dozen countries with a fully federal system of government, in which power is divided between national and state governments.

How income taxes evolved from a funding tool for war into a crucial revenue source for the federal government

Americans have long resisted income taxes. So, how did they become permanent? This overview explains how wartime funding needs, constitutional changes, and economic shifts gave rise to the modern tax system, from the Civil War to the payroll withholding rules we follow today.

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.

The Electoral College was shaped in part to balance North–South power

This article examines how the Electoral College emerged from political compromise, including efforts to placate slave-owning Southern states and concerns that Northern states would dominate a direct national presidential vote.

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

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

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

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

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.

Roughly 43 million US borrowers owe roughly $1.7T in student debt, the second-largest source of consumer debt behind mortgages.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

Hear about the 250-year history of the United States Postal Service, complete with some of its strangest deliveries, important innovations, and the figures that made it an American institution.

The United States has had a tumultuous relationship with Cuba since its 1959 revolution, highlighted by a nuclear crisis and a decades-long trade embargo.

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.

Fireworks make a loud booming sound after exploding due to air expanding faster than the speed of sound.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission

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

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

View the ten deadliest tornadoes in US history.

Iran's Revolutionary Guard Corps is independent of Iran's regular army and is one of the most powerful and influential military-political organizations in the Middle East.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in terms of casualties, forces mobilized, and displacement of civilians.

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.

Recent research found that the brain doesn't seem to massively rewire following amputation—upending earlier beliefs about the cause of phantom limb pain.

The Brothers Grimm were lawyers before they were storytellers, and became interested in fairy tales as they began investigating how rules and customs had been passed down through cultures.

A small portion of The Winstons' 'Amen, Brother,' an obscure '60s gospel record, is the basis for thousands of hip-hop tracks, making it one of the most sampled records ever that's informally known as 'the Amen break.'