A study released on Tuesday by the American Constitution Society for Law and Policy identified a "statistically significant" relationship between ballooning campaign contributions by business interest to state supreme court candidates and pro-business decisions by those courts.

Researchers studied more than 2,345 business-related state high court opinions between 2010 and 2012 and campaign contributions during that same time to sitting state high court judges. As the percentage of contributions from business groups went up, the probability of a pro-business vote by judges — defined as any decision that made a business better off — went up as well.

The study’s author was Joanna Shepherd, a professor at Emory University School of Law. During a teleconference, she said the findings demonstrated that state court elections were becoming increasingly politicized and expensive. She pointed to surveys showing concern within the judiciary and among the general public about the influence of outside dollars on the courts.

"The more campaign contributions from business interests the justices receive, the more likely they are to vote for business litigants when they appear before them in court," she concluded in her report.

According to the report, business groups, lawyers and lobbyists historically contributed the most money in state court elections. Business interest groups gave more than $62.6 million between 2000 and 2009, 30 percent of all contributions. Shepherd cited national and state chambers of commerce as examples of the contributors studied. Lawyers — especially the plaintiffs’ bar and lobbyists — gave $59.3 million, or 28 percent.

Researchers studied 175,000 campaign contribution records from 2010 to 2012 or the most recent year before 2010 when a state supreme court justice was up for re-election. The average justice received $62,400 from business groups. In partisan elections, the report said, justices on average received at least a quarter of all contributions from business groups.

To study the potential influence of those contributions, researchers measured the contribution data against more than 10,000 judicial votes in cases involving a business and a government entity or other litigant; disputes between two businesses weren’t included, Shepherd said. They counted any favorable ruling for the business party as pro-business. Of the votes studied, 49 percent qualified as pro-business.

Twenty-one states use partisan or nonpartisan elections to choose judges for state supreme courts, according to the report, while a governor or the legislature appoints judges in 29 states. Nineteen states hold partisan or nonpartisan elections when a judge’s term is up and 18 states use retention elections, meaning that voters only decide whether a judge should stay on the bench, as opposed to elections in which candidates can challenge an incumbent.

In the remaining states, judges are either reappointed by the governor, legislature or nominating committee, or their appointments are permanent.

The data didn’t show a relationship between campaign contributions and judicial decision-making in states that held retention elections. Campaign contributions were highest in partisan elections.

The researchers reported a stronger relationship between campaign contributions and pro-business judicial decisions by Democrat-affiliated judges. Shepherd speculated that this might be because right-leaning judges tended to "be more ideologically predisposed to favor business interests." The report showed that Republican-affiliated candidates typically received more money from business groups.

Shepherd cited the U.S. Supreme Court’s 2010 decision in Citizens United v. Federal Election Commission as having the most significant effect on campaign contributions in state supreme court elections. Such contributions had risen steadily during the past two decades but were significantly higher post-Citizen United, she said.

"Until reforms are enacted, powerful interest groups’ influence on judicial outcomes will only intensify," she wrote.

Contact Zoe Tillman at ztillman@alm.com.