Leadership of which person was key north's victory in the civil war

Abraham Lincoln was the president and the Commander-In-Chief during the war, which is the highest military rank.
Ulysses Simpson Grant was Commanding General of the Union (North) along with Abraham Lincoln. Many people believe that General Grant was the commanding officer, so I would go with Ulysses Simpson Grant.

Asuffragette was a member of militant women's organisations in the early 20th century who, under the banner "votes for women", fought for the right to vote in public elections, known as women's suffrage.