Even judicial races aren’t immune from the influence of outside spending.

Nearly 63 percent of the TV ads bought in state supreme court campaigns this year were paid for by political parties and outside groups, worrying advocates for integrity in the judicial branch who fear all that spending could lead to distorted rulings. The TV ad data comes from an analysis of Kantar Media/CMAG data by Justice at Stake and the Brennan Center for Justice at the New York University School of Law, both of which work to uphold the integrity of the judicial system. All told, more than $9.1 million has been spent nationwide on TV ads, according to a new analysis by the groups.

“This high level of spending is consistent with the spending we saw in 2010 midterm judicial races,” Alicia Bannon, counsel at the Brennan Center for Justice, said in a statement. “Special interest groups continue to dump money into state Supreme Court races in an attempt to stack the deck in their favor. Voters should feel like our courts are fair and impartial, not political playgrounds where business interests and lawyers can tilt the scales of justice with their pocketbooks.”

Political parties, outside groups, and judicial candidates themselves have spent more than $6.1 million on TV ads for the general election. Toss in primaries and off-cycle elections and that total surpasses $9.1 million, according to government filings and Kantar data. Michigan has seen $2.9 million spent to date, the highest level of ad spending on judicial races of any state this year. Illinois, Montana, Missouri and North Carolina have also seen significant judicial campaign spending this year.

Recent studies have shown that the influx of spending on such races has been associated with a shift in judicial decision-making. Just this week, a review of thousands of state supreme court criminal appeals found that an increase in TV ads was associated with less-favorable rulings for criminal defendants. Advocates for the integrity of the judicial branch fear that an increase in attack ads accusing justices of being soft on crime may be nudging them to increasingly rule against criminal defendants.

Of course, with two weeks remaining until the election, TV ad spending is far from over.