The Second Great Awakening refers to a period of religious revivals at occurred in the United States in the 1830s. After this, many more Americans became practising Christians.
The Second Great Awakening also created in Americans an urge to reform the United States. Reformers began advocating many social and political changes. There were movements to prohibit alcoholic beverages, to increase public education, to support rights for women, to outlaw war, and so on.
One of the movements to arise out of the Reform movements was the Abolition Movement which called for awn immediate end for to slavery.
Thus, the Second Great Awakening and the reform movements that it inspired helped led to more and more Americans, mainly outside of the south, to reject slavery. Originally, the abolition movement did not advocate using political methods to end slavery, but the antislavery movement became political. This led to the creation of the Republican Party and finally to the election of Abraham Lincoln, the first president hostile to slavery. When he was elected, the states of the deep south attempted to leave the United States. The remaining states and the national government refused to allow this and the war began.