There is no single “black vote.” There are many.

Black voters are getting a significant amount of attention these days.

In many ways, it’s a welcome development: After years of helping Democrats secure crucial election victories, black voters are being recognized as an influential voting bloc. This was perhaps most notable in 2008 and 2012, where their increased turnout helped deliver the White House to Barack Obama, the nation’s first black president.

But black voters had been wielding their power even before this, in situations like the 1984 Democratic primary, where the support of black voters single-handedly turned Jesse...