TALLAHASSEE, Fla.  —  Florida's provisional ballot (search) law violates the state constitution because it disenfranchises otherwise eligible voters who show up at the wrong precinct, union attorneys told the state Supreme Court on Wednesday.

Under the Florida Constitution, voters are qualified as residents of a particular county — not as residents in a precinct, San Francisco attorney Jonathan Weissglass told the justices in oral arguments.

Weissglass represents the AFL-CIO (search), American Federation of State, County and Municipal Employees and Service Employees International Union. The unions want Florida's high court to keep most of the provisional ballot law in place but to overturn the provision that requires ballots be cast by voters in the proper precinct.

Attorneys for Secretary of State Glenda Hood and elections officials defended the law, arguing the precinct provision was a reasonable regulation, like closing polls at 7 p.m.

Chief Justice Barbara Pariente questioned whether the court has the power to do anything but throw out the entire law if it finds it unconstitutional.

A similar but unrelated federal lawsuit was filed by the state Democratic Party, alleging Florida's provisional ballot law violates the Help America Vote Act. But a federal judge refused earlier last week to order the state to change its policy.