Any president can change the future. Donald Trump stands out for his ability to change the past, without even trying.
He's already altered perceptions of what happened in America decades and centuries ago. We know that because of a new survey of presidential historians conducted by C-SPAN, asking them to rank presidents on various attributes and overall performance.
The latest scorecard, which included responses from 91 historians, is similar in most respects to those compiled in C-SPAN's first two, in 2000 and 2009. But it holds some surprises that suggest that things look different with Trump in the picture.
Some things are fixed. The greatest president is Abraham Lincoln, who has finished first in each poll. Coming in second, for the second straight time, is George Washington. Franklin Roosevelt is third, just ahead of cousin Theodore.
The worst, three times running, is James Buchanan, who preceded Lincoln and whose indulgence of pro-slavery forces is blamed for helping to bring on the Civil War. Second-to-last each time has been Andrew Johnson, who succeeded Lincoln and was the first president to be impeached (though he was not convicted).
This is the first poll to include Barack Obama, who came out ahead of his most recent predecessors. Obama is ranked No. 12, three spots below Ronald Reagan but ahead of George W. Bush (33), Bill Clinton (15) and George H.W. Bush (20).
Obama is one of the lowest-rated presidents in terms of relations with Congress — worse, somehow, than William Henry Harrison, who died a month after taking office — and got mediocre marks on foreign relations, but scored high on pursuing equal justice for all.
The biggest improvement was registered by Dwight Eisenhower, ranked ninth in 2000 and eighth in 2009. He landed at fifth, jumping over John Kennedy, Thomas Jefferson and Harry Truman, who were ahead of him the last time around.