The Union (North) was lead by the 16th president, Abraham Lincoln. He was a Republican that opposed the expansion of slavery. Unfortunately, he was assassinated by John Wilkes Booth.
Some military leaders of the Union include people like Ulysses S. Grant, William L. Sherman, George Mcclellan, etc. Leaders like Ulysses S. Grant became the future U.S. presidents for their brilliant work in the Civil War.
The Anaconda plan was suggested by Winfield Scott to slowly "choke and suffocate" the South, economically. Then form a blockade around the South to prevent them from trading with the rest of the world (England).