Correct answer
Harry Truman
WW2 ended in September, but FDR died in April, and Truman became the president.
The civil war is what I found
Settling disputes
Deborah is known among the "judges" of Israel. That designation included the sort of dispute-settling we would think of as the role of a judge, but also more general leadership. The Bible book of Judges records the activities of these leaders of the Israelite people during the days before they had a king.
The American civil War was a war fought from 1861 to 1865. It was one of the bloodiest wars.