Historical rankings of U.S. presidents differ depending on what population responds, but polls consistently have George Washington, Abraham Lincoln and Franklin Roosevelt leading in terms of greatness. William Henry Harrison, Franklin Pierce, Andrew Johnson and James Buchanan usually come up at the bottoms of the rankings.
George Washington as the nation's first president almost always gets a great deal of respect in the rankings. What he did for the nation before he became president and the example he set as president are still held in high regard by historians.
Abraham Lincoln's guidance of the nation during one of its most trying periods, the Civil War, puts him at or near the top of the rankings. His dedication to keeping the country united is virtually undisputed by historians.
Franklin Roosevelt's administration was invaluable toward pulling the country out of the Great Depression and through World War II. His unequaled four elections to the office reflect the trust Americans had in him during these days.
Typically toward the bottom of the rankings, William Henry Harrison spent the least time in office of any president, dying only a month after his inauguration. Franklin Pierce allowed for the addition of several new slave states during his term, setting the table for war. Andrew Johnson was the first president impeached and opposed Reconstruction initiatives that included the 14th Amendment. James Buchanan did nothing to stop slavery from spreading. Other presidents frequently mentioned near the bottom are Warren Harding and Richard Nixon.