Final answer:
Lincoln contrasted America four years earlier by focusing on the nation's obligations to the slaves and the process of reconciliation in his second inaugural address.
Step-by-step explanation:
In his second inaugural address, Abraham Lincoln contrasted America four years earlier by focusing on the nation's obligations to the slaves and the process of reconciliation. He suggested that the postwar world might include extending the right to vote to black men. By emphasizing these issues, Lincoln strengthened his argument by showing progress towards equality and promoting national unity.