Who led the U.S. during the Civil War?

The U.S. during the Civil War was led by Abraham Lincoln, who served as the 16th President from 1861 until his assassination in 1865. Lincoln's leadership was characterized by his commitment to preserving the Union and his efforts to abolish slavery, which was a central issue that contributed to the war. His ability to articulate the moral and political dimensions of the conflict helped galvanize support for the Union cause.

Ulysses S. Grant, while an important military leader and later the 18th President, was not the overall leader of the country during the Civil War. He played a crucial role as a general in the Union Army, particularly in achieving significant victories.

George Washington and Thomas Jefferson were key figures in American history, but their leadership occurred much earlier, before the Civil War. Washington was the first President, and Jefferson served as the third, both of whom were influential in the founding and early development of the United States. However, neither was involved in the leadership during the Civil War era.

Thus, Lincoln's presidency and his direct involvement in Civil War policies and decisions make him the correct answer.