…It’s worth recalling that these policies have lasted as long as they have because of compromises — in which Republicans played a crucial part. …

Subsequent history has shown the benefits and defects of each compromise.

Between 1976 and 2010, the African American share of college enrollment rose from 9.4 percent to 14.5 percent, according to the National Center for Education Statistics. The number of black elected officials rose ninefold nationwide between 1970 and 2000; Deep South states have made the most progress. This is revolutionary.

Still, using race as “one factor” has often become a euphemism for using it as the decisive factor. That understandably rubs many Americans the wrong way, especially in a multiethnic society that resembles the old white-black caste system less and less. And access is not the same as success: African American college students graduate at about half the rate of whites.