Shelby County has not made such a request and opposes Section 5 on its face. It is 11 percent African-American, compared with 28 percent statewide.
The high court now may new be prepared to do what it hinted at in a separate Section 5 challenge three years ago.
Roberts authored that 2009 high court ruling, suggesting its days were numbered.
He said the pre-clearance provision raised "serious constitutional questions," and added it "represents an intrusion into areas of state and local responsibility that is unfamiliar to our federal system."
"Things have changed in the South. Voter turnout and registration rates now approach parity," said Roberts, echoing the views Shelby County now makes in its appeal. "Past success alone, however is not adequate justification to retain the pre-clearance requirements."
Until now, the court has avoided the key question over the law's constitutionality.
Some conservative groups have argued that "ancient formulas" are being applied today, not to erase discrimination, but to benefit a particular political party. Some liberal activists counter Section 5 and federal oversight are being demonized by many on the right for purely partisan gain, and to divide Americans again over race.
The case is Shelby County v. Holder (12-96).