How did the Debates of Lincoln vs. Douglas in 1858 create the Landscape of American Society?

The Lincoln–Douglas Debates of 1858 were a series of seven debates between Abraham Lincoln, the Republican candidate for the United States Senate from Illinois, and incumbent Senator Stephen Douglas, the Democratic Party candidate. At the time, U.S. senators were elected by state legislatures; thus Lincoln and Douglas were trying for their respective parties to win control of the Illinois legislat