getty images (3) From left: Bill Clinton, Barack Obama and Donald Trump
The poll, which comes out every four years and launched in 2000, surveys 142 historians, asking them to grade former commanders-in-chief on 10 characteristics, including administrative skills, moral authority and economic management.
Among the grades for individual characteristics, the 75-year-old Trump came in last in moral authority and administrative skills. In terms of overall rankings, he came in 41st — ahead of only James Buchanan, Andrew Johnson and Franklin Pierce.
Buchanan, the nation's 15th president, left behind a troubled legacy due to his stance on slavery (which he believed was an issue of state's rights).
Johnson, the 17th president, was inaugurated following the assassination of Abraham Lincoln, for whom he served as vice president. In 1868, he became the first American president to be impeached, after the House of Representatives charged him with violating the Tenure of Office Act after he removed the secretary of war from his position. The impeachment ultimately failed, however, and he was not removed from office.
Pierce's presidency, meanwhile, is often viewed as being rife with failure, ultimately accelerating the country's course toward the Civil War.
Notably, even William Henry Harrison — the shortest-serving U.S. president, who died just 31 days into his term — was voted ahead of Trump, coming in at 40 on the overall list.
Rice University professor Dr. Douglas Brinkley said in a release that Trump's historic second impeachment shortly before he left office may have had an effect on the rankings.
"This year, people compared which is worse: Watergate or the Trump impeachment?" Brinkley said, referring to the '70s scandal that forced Richard Nixon to resign. "The word 'impeachment' probably cost Nixon a few spots downward this year, and maybe Clinton too."
Among those who topped the list are George Washington, Abraham Lincoln and Franklin D. Roosevelt — at the Nos. 1, 2 and 3 spots, respectively. Theodore Roosevelt and Dwight D. Eisenhower were Nos. 4 and 5.
Lincoln also topped C-SPAN's surveys in 2000, 2009 and 2017. Washington, Franklin D. Roosevelt and Theodore Roosevelt also retained their top five status for the fourth time.
"What stands out to me here is the stability," presidential historian Richard Norton Smith said in a press release announcing the results of the survey. "It's interesting, particularly at the top and bottom of the list, how little significant movement there has been. By contrast, the living presidents seem much more likely to fluctuate. It's almost as if there was a boomerang effect where historians go overboard a bit when presidents leave office and they are at the nadir of their partisan reputation, and then they graduate to a less political status."
Among recent presidents, Bill Clinton's ranking has fluctuated through the survey's history. Clinton began at 21 in 2000, the first year the survey was released, coming at 15 in 2009 and 2017 and declining this cycle to 19.
Barack Obama rose to 10 from his spot at 12 in 2017, while George W. Bush continued a steady ascent, coming in at 29, from his No. 33 ranking in 2017.
As the survey only allows respondents to grade former presidents, Joe Biden is not among those featured on the list.
Trump has been graded more favorably in other polls, such as a 2020 Gallup poll in which Americans found him to be admirable, edging out Obama, who ended a 12-year run as the most admired man in the annual survey.
Since those results were released, however, the final weeks of his term were shadowed by his impeachment after a mob of his supporters stormed the U.S. Capitol in a deadly insurrection.