Editor’s Note: This article has been revised and technically updated in August 2025 to improve its structure and readability, while fully respecting its original content.
Almost a century after its independence, the United States of America suffered the greatest political crisis in its history. The discrepancies between the member states nearly caused the project generated by the original Thirteen Colonies to fail. Ultimately, the victory of the Federation’s defenders in a bloody Civil War allowed the country to emerge stronger from the crisis and, a few decades later, to occupy a privileged role in the international order.
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The Root of the Conflict: The Issue of Slavery
The U.S. Constitution enshrined the sovereign right of each state to decide on the matter of slavery. However, by the mid-19th century, public opinion in favor of freedom for enslaved people grew, particularly along the Atlantic coast. In contrast, a movement defending the enslavement of African Americans solidified in the southern territories.
The dividing line was established by the Missouri Compromise of 1820, which created a balance between eleven free states and eleven slave states. Four decades later, the confrontation reached its peak. The election of the Republican Abraham Lincoln, who declared that slavery was a moral issue for Congress to decide, was the final trigger. In response, seven states—South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, and Texas—seceded from the union, forming the Confederate States of America in February 1861.
The Armed Conflict (1861-1865)
In April 1861, Abraham Lincoln declared war on the Confederates. The remaining slave states then took sides: Arkansas and North Carolina joined the Confederacy, while Delaware and Kentucky remained neutral. The conflict between the Union (the North) and the Confederacy (the South) lasted until May 1865.
The North based its strategy on its demographic and industrial potential, as well as its superior infrastructure and command of the sea. The South, on the other hand, had more experienced military commanders and a better-trained army. This kept the balance of the war even until mid-1863. The Battle of Gettysburg was decisive in the defeat of the Confederacy, tipping the scales definitively in favor of the North. The armistice was finally signed, leading to the reconstruction of the South and the abolition of slavery.
The Aftermath: Construction of an American Giant
In the years following the conflict, the northern states benefited greatly from industrial profits and increased exports. The South, however, was economically devastated. The ensuing period of Reconstruction, though selective, allowed the country as a whole to become an industrial and political giant.
The unstoppable growth experienced by the U.S. throughout the latter part of the 19th century turned the nation into a great power. This was reflected in its imperialist policy, exemplified by the purchase of Alaska from Russia (1867) and the war against Spain (1898). The U.S. emerged from its traditional isolationism, becoming the arbiter of American continental politics and a major power in the Pacific. Thus arose the concept of “Manifest Destiny”: the role of Americans as defenders of freedom.
