PORTLAND – A nonprofit political group has filed a friend-of-the-court brief with the Maine supreme court in support of a lower court decision to reject petitions filed with the secretary of state’s office calling for a referendum on a government spending cap.

Democracy Maine cited court cases around the country to support its argument that Secretary of State Matthew Dunlap did not have the discretion to accept petition signatures for a so-called taxpayer bill of rights, or TABOR, after the statutory deadline.

The citizen’s initiative process to get referendum questions on the ballot has clear rules, said Jon Crasnick, executive director of Democracy Maine. The group’s filing concerns itself with the process, not with the substance of the initiative, he said.

“Strict compliance with those rules is necessary to protect the integrity of the process,” Crasnick said. “Otherwise, the system becomes arbitrary and capricious, leading to confusion and uneven application of the law.”

TABOR supporters turned in petitions calling for a referendum with 54,127 signatures to the secretary of state on Oct. 21, 2005.

Another 4,024 signatures were submitted the next business day, Oct. 24. The failure to deliver all the petitions by the earlier date was attributed to an oversight.

Critics said Dunlap erred by allowing the additional signatures to be submitted. Without those signatures, the petitioners failed to meet the threshold of at least 50,519 signatures.

A legal challenge was filed against Dunlap’s decision, and Justice Donald Marden this month reversed the decision. If Marden’s ruling stands, it will block a statewide vote on the initiative.

A notice of appeal was filed in the Maine Supreme Judicial Court the next day on behalf of Mary Adams, who championed the petition effort. The TABOR initiative would limit annual spending increases for state and local governments and schools to the rate of inflation plus increases in population.

Arguments are scheduled to be heard before the supreme court on April 25.