Summary
Highlights
The period begins with the popular idea of Manifest Destiny, driving Americans westward. Motivations included land, resources, opportunities for wealth, and religious freedom (e.g., Mormons in Utah). Government policies like the Homestead Act and Pacific Railroad Act facilitated this expansion. The US also expanded its influence transnationally, with treaties opening trade with China and Japan.
President James K. Polk, focused on westward expansion, negotiated Oregon and provoked war with Mexico over the Texas border. The resulting Mexican-American War (1846-1848) led to the Treaty of Guadalupe Hidalgo, ceding vast lands (the Mexican Cession) to the US. This new territory immediately sparked fierce debate over whether slavery should be allowed, exacerbating tensions with Native Americans and Mexican-Americans.
The question of slavery in the Mexican Cession led to the Wilmot Proviso (which failed) and eventually the Compromise of 1850. This compromise included California as a free state, popular sovereignty in Utah and New Mexico, a ban on the slave trade in D.C., and a stricter Fugitive Slave Act. The Fugitive Slave Act particularly angered Northerners, leading to widespread resistance and further deepening sectional divisions.
Massive immigration from Ireland and Germany in the 1840s (due to revolutions and famine) flocked to Northern cities, forming ethnic communities. Meanwhile, abolitionist movements gained momentum, with figures like Frederick Douglass and Harriet Beecher Stowe (Uncle Tom's Cabin) exposing the injustices of slavery. These factors, alongside economic differences, contributed to an irreconcilable divide between the North and South.
Further attempts at compromise failed spectacularly. The Kansas-Nebraska Act (1854) introduced popular sovereignty, leading to 'Bleeding Kansas' where pro- and anti-slavery settlers clashed violently. John Brown's radical actions, including the Harpers Ferry raid, intensified divisions. Weak presidencies, legislative violence (e.g., Brooks-Sumner affair), and the Supreme Court's pro-slavery Dred Scott decision (1857) rendered all branches of government ineffective in resolving the conflict, making war inevitable.
The highly contested 1860 presidential election saw four candidates, with Abraham Lincoln winning without Southern support. His victory prompted South Carolina to secede, followed by six other states forming the Confederate States of America. Lincoln vowed to preserve the Union, and the attack on Fort Sumter in April 1861 marked the official start of the Civil War.
The Union had advantages in population, industry, and infrastructure, while the Confederacy had skilled generals and home-field advantage. Early battles like Bull Run showed the war would be long. The Union employed the Anaconda Plan, while the Confederacy focused on defense and seeking European intervention. Key turning points in 1863 included the Union victories at Gettysburg and Vicksburg, splitting the Confederacy. Ulysses S. Grant and William T. Sherman's strategy of 'total war' devastated the South, leading to Lee's surrender in 1865 and the end of the war, with over 600,000 casualties.
Initially, Lincoln framed the war as preserving the Union. However, after the Battle of Antietam, he issued the Emancipation Proclamation (1863), freeing enslaved people in Confederate territories and redefining the war as a fight against slavery. This also discouraged European intervention on behalf of the Confederacy and led to nearly 200,000 African-American soldiers fighting for the Union. Lincoln's Gettysburg Address further solidified the war's purpose as a fight for democracy and national unity.
After the Civil War, the US entered Reconstruction to rebuild the South and integrate freed slaves. Lincoln's lenient 10% Plan was followed by President Johnson's similar approach. However, Radical Republicans in Congress pushed for a harsher plan to punish the South and protect Black rights, leading to Johnson's impeachment. Amendments abolished slavery (13th), granted birthright citizenship and equal protection (14th), and gave Black men the right to vote (15th). Despite initial gains, the South resisted with Black Codes, sharecropping, lynchings, and white supremacist groups like the KKK. Supreme Court rulings like the Slaughterhouse Cases diminished federal protection for civil rights.
Reconstruction ultimately failed due to Southern resistance and Northern weariness, culminating in the Compromise of 1877. This deal removed federal troops from the South in exchange for a Republican president, effectively ending Reconstruction and allowing white Southerners to regain control. This led to decades of Jim Crow laws, segregation, and voter suppression. Although a failure in its immediate goals, the 14th and 15th Amendments laid the legal foundation for the Civil Rights Movement a century later.