Who could lead such a dialogue in a civilized, useful way? Bill Clinton, who launched a similar conversation in 1997, could help. Gates, the Harvard professor, knows a thing or two. Or Jim Webb, the Democratic senator from Virginia who’s criticized diversity programs for favoring high-income minority candidates over low-income whites. Or Rep. John Lewis (D-Ga.), one of the surviving heroes of the civil rights movement that made Obama’s presidency possible.

The president doesn’t need to teach on every issue. But on this one, he might consider asking someone else to.