A seismic U.S. Supreme Court ruling has pushed Louisiana to cancel its Congressional races, but early voting begins as scheduled Saturday for many other elections on the May 16 ballot.

Louisiana Republicans have eliminated an elected position days before an exoneree who overwhelmingly won the New Orleans-based clerk seat was set to take office.

“The basis of the Voting Rights Act was to ensure that African Americans had both equal access to the polls and equal representation in governmental bodies. Today’s decision is yet another blow in a d...