“Robinson had originally planned to include American frontiersmen like Lewis and Clark and Native Americans, including Sacagawea. But Borglum, eyeing an opportunity to make a national statement, dissuaded the historian. Instead they settled on the four American presidents, two of them slaveholders and all of them viewed by Native Americans as racist.” [1]
[0] https://en.wikipedia.org/wiki/Gutzon_Borglum [1] https://www.washingtonpost.com/history/2020/07/03/mount-rush...