The Civil War was essentially inevitable. Ever since Eli Whitney’s invention of the cotton gin in the 1790s, the South had been on a completely different economic and social path from the North. In the 1850s, social and political developments, including the publication of Uncle Tom’s Cabin, the Fugitive Slave Act, Bleeding Kansas, the Dred Scott decision, and John Brown’s raid on Harpers Ferry, drove the regions further apart. Although the North and the South tried to reconcile their differences with major political compromises in 1820 and in 1850, both attempts failed.

The cotton gin transformed the slave South completely in the early 1800s, when plantation owners abandoned almost all other crops in favor of the newly profitable cotton. To raise more cotton, planters also purchased more slaves from Africa and the West Indies before the slave trade was banned in 1808. Thousands of blacks were brought into the United States during these years to tend to cotton fields. The size of plantations increased from relatively small plots to huge farms with as many as several hundred slaves each. Because the entire Southern economy became dependent on cotton, it also became dependent on slavery. Although Northern factories certainly benefited indirectly from slavery, Northern social customs were not tied to slavery as Southern customs were.

Events in the 1850s proved that the North-South slavery divide was irreconcilable. Harriet Beecher Stowe’s 1852 novel Uncle Tom’s Cabin, which awakened Northerners to the plight of Southern slaves, became an overnight bestseller in the North but was banned in the South. The book was particularly powerful in the wake of the 1850 Fugitive Slave Act, which forbade both Northerners and Southerners to assist runaway slaves—a law that troubled even those who had shown little sympathy for the abolitionist cause. The “Bleeding Kansas” violence of 1856 between proslavery groups and Free-Soilers shocked people in the North and in the South and demonstrated just how strongly the opposing camps felt about their beliefs. In 1857, the Dred Scott decision outraged Northerners because it declared the Missouri Compromise unconstitutional and effectively opened the North to slavery. Finally, John Brown’s 1859 raid on Harpers Ferry, Virginia, and subsequent execution proved to be the last straw for many on both sides. Northerners mourned the “martyr” Brown, while Southerners celebrated his death as a great victory. These events of the 1850s convinced Americans in both the North and South that there could be no compromise on the slavery issue.

Both sides had tried to resolve the issue on numerous occasions, but to no avail. The Missouri Compromise of 1820 had established the 36˚ 30' parallel as the border between the slave states and the free states. This compromise satisfied both sides for a while but eventually became too restrictive for the South. The Compromise of 1850 likewise sought to end the slavery debate after the Mexican War and the Wilmot Proviso raised the question of slavery in the West—but in the end these peaceful resolutions were also unsatisfactory. As a result, in light of the deep political, economic, and social divides, as well as the failure of compromise attempts, armed conflict was thus inevitable.

When South Carolina seceded from the Union in 1860, four of the other fourteen slave states—Maryland, Delaware, Kentucky, and Missouri—chose to remain in the Union rather than join the Confederacy. West Virginia eventually seceded from Virginia in 1863 to become a nonslave state in the Union, too. These five border states were crucial to the North both geographically and economically. As a result, Lincoln was careful to maintain the border states’ allegiance and refrained from pursuing any policies that might be too bold and potentially alienating to slave owners in those states. Ultimately, the North’s possession of the border states directly affected the outcome of the war.

First and foremost, the border states provided a physical and ideological buffer between the North and South: if Maryland had seceded, Washington, D.C., would have been entirely surrounded by Confederate territory. Lincoln was acutely aware of Maryland’s importance: in the spring of 1861, he even turned to military force and instituted martial law in the state to keep it loyal to the Union.

The border states were just as important economically, especially because Maryland and Delaware contained many factories and industrial complexes. Had just those two states joined the Confederacy, they would have doubled the South’s manufacturing capability. Lacking these factories, though, the South ended up starving under the Union’s naval blockade. Indeed, the Civil War was in many ways an economic war, and doubling Southern manufacturing output could have seriously altered the duration and even the outcome of the conflict.

Finally, the border states’ loyalty to the Union showed that slave states had an alternative to secession. The South, for its part, had justified secession by claiming that slave states had to secede to save their “peculiar institution” and their way of life. The fact that the border states—where slavery was practiced—remained in the Union severely weakened this claim.

For all these reasons, Lincoln remained careful not to offend slave owners in the border states. The most notable example of his sensitivity to this issue is the 1863 Emancipation Proclamation, which declared slaves free in only the secessionist states—not the loyal border states. Ultimately, Lincoln’s measures were effective, and the continued loyalty of the border states was a major factor in the Union’s eventual victory.

Although both the North and the South thought they would easily win the Civil War, the South was in many ways doomed from the start. Indeed, by 1864 the South was in ruins, its economy destroyed by blockade, hyperinflation, and the North’s campaign of total warfare. In the end, it was the Northern economy and deficiencies in the Southern political system that won and lost the war.

When war broke out in 1861, both sides thought they would win quickly and easily. The Union had experience and international recognition, a robust industrial economy, a strong federal government, twice the population of the South, and twice as many young men for its army. On the other hand, the new Confederacy had cotton (which it believed to be superior to industry), had better military commanders, and believed it could bring Britain into the war on its side. Just as important, however, was the South’s feeling of righteousness that followed secession: Southerners felt they were carrying on the tradition of overthrowing tyrannous governments that the founding fathers of the United States had begun. In addition, Southern soldiers, fighting on their home territory, also had an intense desire to fight to protect their homes and families.

By the end of 1864, however, the South lay in ruins, and very little remained of the once-proud Cotton Kingdom. The price of goods was so high and money was so worthless that it cost Southerners in some places several hundred Confederate dollars to buy a single loaf of bread. As a result, hunger and malnutrition became rampant. In addition, much of the landscape from Tennessee to Georgia and up to South Carolina had been razed by General William Tecumseh Sherman’s troops on their March to the Sea. Many slaves in the South effectively emancipated themselves by refusing to work and flocking to Union lines in droves. The North, meanwhile, was in many ways better off in 1864 than it had been before the war, for the economy had experienced an enormous boom during the war years and had set the industrial machine into high gear.

This industrial boom in the North, coupled with the Richmond government’s inability to provide cohesive leadership, won the war for the Union. Virtually all the effective measures passed by the Union government went unanswered by the Confederacy. Congress in Washington, D.C., for example, stabilized the Northern economy early on in the war by passing the Legal Tender Act, replacing the hundreds of different state and private bank currencies with a single federal dollar. Because this “greenback” currency was supported by the U.S. Treasury, investors knew it was safe and reliable. The National Banking Act also gave the federal government unprecedented control over the banking system and the economy as a whole. The Confederate government, on the other hand, dominated by states’ righters, never enacted any such federal laws but instead continued to reserve most powers for the individual states. This inaction, combined with the devastating economic effects of the Union’s naval blockade of the South, left the Confederate war effort doomed early on.