Abraham Lincoln was the President of the Union Army.
Grant
defeat the Confederate Army
First of all, Vicksburg is not a state, it's a city. Second, Robert E. Lee was approached by Lincoln to command the Union army because of his views against slavery. Lee declined saying that if his home state of Virginia seceeds from the Union, he will go with it.
Tennessee seceded from the Union after President Lincoln was elected and began raising an army. =]
d
The president of the Union. The commander-in-chief of the Union Army.
General Robert E. Lee. He was asked by President Abraham Lincoln if he would command the Union forces but he declined, with much difficulty, saying that he could not fight against his state, Virgina. While Robert E. Lee was still a colonel in the US Army, it's clear he was offered a commanding position in the Union army, however, the actual US general making this offer was probably Winfield Scott. Nevertheless, President Lincoln would have approved of this. Also, Lee's position in the Confederate army at first was a minor commission. Later he would advance and become the leading, most highly regarded Confederate general.
He did not. The war was ended by the Union Army defeating the Confederate Army.
Abraham Lincoln
Putnam
General Grant