Final answer:
John Brown's raid on Harpers Ferry increased tensions between the North and the South and further divided abolitionists and pro-slavery advocates. Southerners became convinced that slave uprisings could never succeed, leading to increased support for secession and eventually the Civil War.
Step-by-step explanation:
John Brown's raid on Harpers Ferry had a significant impact on the United States. The raid increased tensions between the North and the South, leading to a further division between abolitionists in the North and pro-slavery advocates in the South. Southerners were incensed by the raid and viewed it as an attack on their way of life. As a result, many southerners became convinced that slave uprisings could never be successful, leading to increased support for secession and ultimately contributing to the outbreak of the Civil War.