Schools across the country are adorned with posters of the U.S. presidents and the years they served in office. U.S. history textbooks describe the accomplishments and challenges of the major presidential administrations — George Washington had the Revolutionary War, Abraham Lincoln the Civil War, Teddy Roosevelt the Spanish-American War, and so on. Children’s books put students on a first-name basis with the presidents, engaging readers with stories of their dogs in the Rose Garden or childhood escapades. Washington, D.C.’s Smithsonian Institution welcomes visitors to an exhibit of the first ladies’ gowns and White House furnishings.

Nowhere in all this information is there any mention of the fact that more than one in four U.S. presidents were involved in human trafficking and slavery.