I am surrounded by history. Among the many items in my office is a bust of Thomas Jefferson, a bust of Abraham Lincoln and a photo of the undefeatable Jackie Robinson.

And sitting on a bookshelf is an iron ankle shackle.

I pick it up sometimes. Here is history so many would like to ignore or forget. But we do so at our peril.

Today, African Americans hold positions of tremendous prestige, including, of course, the highest office in the world. But that is not enough. We learned quickly after Barack Obama’s election that there is no such thing as a post-racial America. Centuries of deep troubles do not dissolve in eight years.

Along comes the National Museum of African American History and Culture. It is more than a repository of a people’s history. It is an opportunity. The museum’s location and proximity to other iconic monuments — Washington, Jefferson and, of course, Lincoln — will speak to what has always been true about our original sin: its centrality to the American story. ...