Who did the general in the Union Army during the American Civil War pave the way for the surrender of Fort Donelson, who later became the 18th President of the United States?
James M. Tuttle:  He led the first Union troops that entered the enemy-held Fort Donelson in 1862, paving the way for the fort's subsequent surrender to Ulysses S. Grant and opening the Cumberland River as an avenue of invasion of the South. Ulysses S. Grant: Ulysses S. Grant, born Hiram Ulysses Grant , (April 27, 1822 – July 23, 1885) was the Commanding General of the United States Army at the end of the American Civil War and later the 18th President of the United States from 1869 to 1877.
Ulysses S. Grant