Washington (CNN) -- The U.S. Supreme Court has made a decision ina case examining whether a key enforcement provision of the landmark 1965 Voting Rights Act should be struck down. Details of the ruling are expected shortly.

The case involves Section 5, which gives federal authorities open-ended oversight of states and localities with a history of voter discrimination. Any changes in voting laws and procedures in the covered areas -- which include all or parts of 16 states -- must be "pre-cleared" with Washington.