While Washington politicians argue over the role of money in federal elections, a growing number of states are starting to grapple with their own challenge: a tide of special-interest money flowing into local judicial races.

An exhaustive study scheduled to be released Monday shows that spending on state Supreme Court elections has more than doubled over the past 10 years, to $207 million, mirroring the surge in contributions and expenditures for other kinds of political races during the same period.

The report, produced by a trio of nonpartisan policy groups, found that much of the increase has been fueled by outside groups funding attack ads of the kind commonly found in partisan races for the White House, Congress or governors' mansions. Industry groups, trial lawyers and others are increasingly targeting specific judges for removal over rulings that hurt their financial bottom line, the report shows.

The findings come amid mounting evidence that 2010 is likely to mark a new watershed for spending in a midterm election year. The study also underscores a growing debate in legal and political circles over the influence of campaign money in judicial races, particularly in 22 states where top judges face challengers or 16 others that hold "retention" elections for judges.

U.S. Supreme Court Justice Ruth Bader Ginsburg has joined her former colleague Sandra Day O'Connor in calling on states to give up the practice of electing judges, arguing that raising campaign money and promising outcomes on the bench is antithetical to a fair judicial system.

In an introduction to the new report -- produced jointly by the Brennan Center for Justice, the National Institute on Money in State Politics and the Justice at Stake Campaign -- O'Connor says the growing influence of special interests is undermining public confidence in the courts. "Left unaddressed, the perception that justice is for sale will undermine the rule of law that the courts are supposed to uphold," O'Connor wrote.

The debate over judicial elections comes amid a flurry of defeats for proponents of campaign finance restrictions, including a U.S. Supreme Court decision allowing corporations to spend an unlimited amount of money on political races.

Interest groups and political parties on both sides have already begun ramping up spending on key state court races in Alabama and Michigan. In Iowa, conservative activists are targeting justices involved in the state's decision to legalize gay marriage.

The new study shows that total spending in state Supreme Court contests has rocketed from less than $6 million at the start of the 1990s to more than $45 million during the 2008 election cycle. Much of the activity is focused in a handful of states with open elections for their high courts, including Alabama, Pennsylvania, Ohio, Illinois and Texas, the data show.

The spending is driven in part by outside interest groups on the right, such as the Chamber of Commerce and its affiliates, and on the left, including unions and trial attorneys.

In perhaps the best-known recent example, the chief executive of Massey Coal Co. spent $3 million to help elect a West Virginia high-court judge, who then participated in a case overturning a $50 million verdict against the company. The case led to a landmark ruling from the U.S. Supreme Court, which found that excessive campaign contributions can create an unconstitutional threat to a fair trial.

"What you've got now is an industrialized apparatus to turn high-court races into arms races," said Bert Brandenburg, executive director of Justice at Stake.

"There's an instinct among the public that courts are supposed to be different than the rest of the government, at least somewhat. The question is whether the courts can stay impartial if they become overwhelmed with cash," Brandenburg said.

In Wisconsin, a pair of high-profile contests in 2007 and 2008 attracted millions from outside groups focused on whether to curb lawsuits and damages awards. Those on the winning side in both races included the conservative Club for Growth, while organized labor and progressive groups spent heavily on the losers, the study shows.

The influx of hardball politicking prompted Wisconsin to enact public financing of its Supreme Court races in 2009, a system that is now under challenge in the courts.

Jeff Patch, spokesman for the Center for Competitive Politics, which is challenging the Wisconsin system, says complaints about spending on judicial races are overblown.

The group does not take a position on whether states should hold judicial elections, but those that do must not limit the free-speech rights of voters or candidates, he said.

"Part of our argument is that there isn't a different First Amendment standard for judicial campaigns," Patch said.