HARRISBURG — Candidates for Pennsylvania’s highest court Monday were winding down a $3 million-plus campaign for state Supreme Court, marked by blistering attack ads and big money from special interests.

The battle for a single open seat between Democrat Jack Panella and Republican Joan Orie Melvin tops today’s statewide election ballot that also features contests for four openings on the state Superior Court and two on the Commonwealth Court.

Voters across the state also will be electing numerous city and county officials, including a new district attorney in Philadelphia, mayors in Pittsburgh, Harrisburg and York and dozens of new county judges.

Turnout at the polls is expected to be low. Terry Madonna, a professor and pollster at Franklin & Marshall College in Lancaster, says he expects no more than one-quarter of the nearly 8.5 million voters to cast ballots in an election in which only the Supreme Court race has attracted statewide news coverage.

“Not in Pennsylvania’s history has that been a ballot driver,” he said.

Both Supreme Court candidates are sitting judges on the Superior Court – Panella in Bethlehem, Melvin in Pittsburgh. A Melvin victory would restore the one-seat Republican majority that the party lost in 2007, while a Panella win would sustain the Democrats’ 4-3 edge.

Justice Jane Cutler Greenspan, a Democrat, currently holds the position but agreed not to seek a full 10-year term when she was appointed to complete the term of the late Chief Justice Ralph Cappy after he retired last year.

On Monday, both candidates were out campaigning.

“We’ve certainly done everything we can to explain why he’s the best candidate,” said Panella campaign spokesman Dan Fee.

At the state Republican Party headquarters in Harrisburg, spokesman Mike Barley said Melvin supporters felt “very optimistic” about her prospects.

Panella, 54, has raised the most campaign cash by far – more than $2.5 million – mostly from lawyers and various organized labor groups.

Trial-lawyer groups in Philadelphia and Williamsport alone have given $1.3 million, according to campaign finance reports on file Monday.

Melvin, 53, has charged that Panella’s reliance on special-interest money may compromise his objectivity on the bench.

Panella, insisting that cases will be judged on their merit, said that fundraising is a necessary, if distasteful, part of running a judicial campaign and that Melvin also has accepted special-interest money.

Panella and Melvin, who both received the top “highly recommended” ratings from a state bar panel, devoted the final days of their campaign to attacking each other in TV ads.

A Panella ad warned female voters that Melvin “wants to take away our rights, including the right to choose.”

In fact, the claim referred to Melvin’s dissent – along with two other female judges on the Superior Court – on a ruling in favor of a woman who wanted to pursue a malpractice claim against a doctor with whom she had a consensual sexual relationship while he was treating her for anxiety and depression.

The dissenters concluded that the doctor’s behavior was unethical, but did not constitute malpractice.

An anti-Panella ad put up by the state Republican Party sought to tar Panella with a scandal in which a pair of Luzerne County judges allegedly took millions of dollars in kickbacks to place juveniles in privately owned detention centers.

The ad charged Panella “turned his back on our kids” when he and fellow members of the state Judicial Conduct Board received an anonymous complaint about one of the judges in 2006, more than two years before criminal charges were filed. Federal prosecutors in the corruption case have said the board acted properly in swiftly forwarding the complaint to them.

The election outcome could lock in the partisan lineup on the Supreme Court for five years. No other changes in the court’s makeup are anticipated before 2014, when Chief Justice Ronald Castille would reach the mandatory retirement age of 70.

Some political observers believe control of the high court could be crucial in the legislative redistricting that will follow the 2010 census.

But lawyers from both parties say that is unlikely, noting that the justices have not overturned any of the four redistricting plans that have been hammered out since the task was turned over to bipartisan panels under a constitutional amendment approved in 1968.