Answer:
Abraham Lincoln belived that slavery was bad completely and wanted to abolish it. When his election prompted the secession and the war started he made the emancipation proclamation which effectively freed all slaves on rebel territories and later he was the creator of the 13th amendment which permanently outlawed slavery in all American territories.
Contrary to him Stephen Douglass believed that democracy should be the biggest way to solve the slavery issue. He wasn't against slavery nor for it on a federal level, what he wanted was for the the states to decide democratically through popular sovereignty and that the federal government would not interfere with their elections.
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Lincoln and Douglas believed that slavery was bad and they illustrated ways on how it can be solved.
Slavery simply means a condition where an individual is owned by another person. Slaves are considered as property.
Abraham Lincoln was against slavery and he seeked ways to abolish it. He was vital in creating the 13th Amendment which was against slavery.
Stephens Douglas believed that democracy should be used in curbing slavery. He believed everyone has his or her rights and no one should deny others such rights.