Raleigh, N.C. — Two political-action committees affiliated with an anti-abortion group have filed a federal lawsuit to challenge North Carolina's law allowing public funding of judicial campaigns.

North Carolina Right to Life PAC and North Carolina Right to Life Committee Fund for Independent Political Expenditures want the law declared unconstitutional, claiming that it violates their free speech rights.

Under the Voter-Owned Elections Act, judicial candidates who apply for public financing cannot obtain large contributions from individuals or special-interest groups. Whenever donations to a candidate who chooses to seek private contributions top a specified threshold, the state releases matching funds to the candidate's opponents who have signed up for public financing.

"This matching funds scheme imposes a substantial burden on the speech of privately financed candidates and independent expenditure groups while releasing all publicly financed candidates from their agreed-to expenditure limits," the two groups said in their suit.

The groups tried to overturn the law five years ago, but both federal district and appellate courts ruled against them. They said they are making a second run at the law after the U.S. Supreme Court struck down a similar matching-fund law in Arizona.

Since their initial suit, the groups said, they haven't provided financial support for any state Supreme Court candidate "for fear that the $240,100 trigger for matching funds for candidates ... would be pulled and cause funding to go to a candidate they did not support."

Their reluctance to contribute to the campaigns of candidates they support is evidence that their free speech rights are being "chilled" by the state law, they argue, asking that the law be overturned in time for the 2012 election.