James Buchanan was the 15th President of the United States, serving from 1857 to 1861. He was a member of the Democratic Party and served as a congressman and senator before becoming president. During his presidency, he faced the growing tensions between the North and South, which ultimately led to the Civil War. He was criticized for his inaction and inability to prevent the war, and is often considered one of the worst presidents in American history. Despite his efforts to preserve the Union, he was unable to prevent the secession of several Southern states and the start of the Civil War.