Abraham Lincoln was President of the United States. When some southern states decided to secede, they elected their own "president" Jefferson Davis. Lincoln remained President of the United States - all the United States - he just wasn't recognized as such by the southern states that seceded. He was not "President of the North".
Abraham Lincoln
Abraham Lincoln.
Jefferson Davis
Abraham Lincoln was the North's president, and in the south, Jefferson Davis.
Abraham Lincoln was the president when Abraham Lincoln was the president.
Abraham Lincoln
Abraham Lincoln was in the civil war in which he convinced the north and the south to stop fighting
Abraham Lincoln for the Union; Jefferson Davis for the Confederacy
Abraham Lincoln was president of the Union, or the North, and Jefferson Davis was president of the Confederate States.
Abraham Lincoln
Abraham Lincoln
The President of the US, Abraham Lincoln.