Cause:
The cultivation of cotton progressed under very different conditions in the North and South. In the North the white man had to work vigorously to overcome the disadvantages of the soil. In the South the negro labourer could be used with profit to his owner, and was held as a slave. By 1860 the thirteen original states were enlarged to thirty-three. The territories of the North-east found their prosperity in free labour, the South throve on the cotton crop and continued to exploit negro labour. The Southern states gradually combined together, and between 1830 and 1850 gained a predominant voice in the control of Federal affairs. The North also became consolidated, and a strong movement against slavery grew up, chiefly owing to the efforts of W. Lloyd Garrison. A new Republican party gained strength in its opposition to the dominating differences of the South, and sectional political differences were intensified. The prospect of the abolition of slavery was not the only issue. The South resented the idea that coercive measures might be used to keep the lower South in the Union. They believed this to be an attack on the doctrine of the sovereignty of states. A widespread feeling in favour of secession grew up.