Lincoln scholars rush to correct Kamala Harris, but she was almost certainly repeating a lie crafted specifically for the occasion by a historian. It wasn't some sort of "error," nor is it only a reflection on her personally. People did look to an "expert" for confirmation.

He's a presidential historian, and he wasn't confused. Brief research indicates he has a particularly strong understanding of what Lincoln was up to in 1864. And he isn't an academic--the problem is far broader.

The Abraham Lincoln Presidential Library and Museum drama of the last few years is hardly atypical. It's the exact same thing, over and over. An inability to admit error and a fixation with shutting down dissenters, as the whole ship goes down.

https://www.antiquesandthearts.com/when-hats-drop-as-alplm-nears-conclusion-on-lincoln-top-hat-a-look-at-what-it-really-cost/

This one was even more disingenuous--and the real story is much more interesting.

This misrepresentation was also pushed, at length, by Harold Holzer, a historian who has written many books on Lincoln, including one on his manipulation of the press. https://www.cnn.com/2020/09/26/opinions/lincoln-reelection-lessons-for-trump-holzer/index.html