The Justice Department also said the Supreme Court had, in recent years, narrowed the scope of some aspects of the Voting Rights Act.

Justice Anthony Kennedy, who could prove a swing vote in the Alabama dispute, noted in an earlier unrelated case involving Section 5 that "racial discrimination and racially polarized voting are not ancient history."

But it may be Chief Justice John Roberts who would exercise the power to lead the tricky but crucial opinion-writing exercise in coming weeks.

That is because he authored that 2009 high court ruling, suggesting Section 5's 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."

The court for three years avoided the key question over the law's constitutionality.

Civil rights supporters worry the court's five conservative members will strike down this and another separate, pending appeal over affirmative action in public college admissions.

Any dispute about voting slips inevitably into politics and efforts by both Republicans and Democrats to preserve their power base.

Section 5 lawsuits have been acute in the past two years. They involve challenges to constitutionally mandated boundary changes in state and congressional districts based on the 2010 census, new, stricter voter identification requirements, and reductions in early voting periods.

Those fights are now clogging the federal courts.

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.

In Shelby, both sides know the nation is watching and know the stakes will ripple widely.

"I'm not saying everything's perfect," Ellis tells CNN. "But I'm saying, very few of the non-covered jurisdictions can give you a success story like I've just given you out here in Shelby County."

"I agree that things have changed in the South and they are better, but they haven't reached the point where we could do away with Section 5 yet," says Jones, senior pastor at New Mount Moriah Missionary Baptist Church in Calera. "It's a lot better but it still lives, discrimination still lives and I'm not willing to trust [voting enforcement] into the hands of people who motives are not pure."

The case is Shelby County v. Holder (12-96).