PORTLAND — Maine’s highest court is asking the state House of Representatives and other interested parties to weigh in on the constitutional questions surrounding the business activity of state Treasurer Bruce Poliquin.

The Maine Supreme Judicial Court has requested briefs that address questions submitted by the House and the question of whether the matter is important enough to warrant the court’s opinion.

The court set a March 16 deadline for briefs and will accept briefs in response to those until March 23.

The House voted unanimously last week to ask the Supreme Court to review two questions about what constitutes “trade or commerce” by a treasurer and one question about how business activity would affect a treasurer’s status, considering that the Maine Constitution forbids the treasurer from engaging in private business.

Poliquin is a Republican who ran for governor in 2010 and is a candidate for the U.S. Senate seat being vacated by Olympia Snowe. He has been a vocal critic of Democrats, including Dale McCormick, director of the Maine State Housing Authority.

He applied to the Phippsburg Planning Board last year for a permit to expand one of his businesses, the Popham Beach Club. He also owns a company that is developing condominiums near the club.

Poliquin did not return a call seeking comment Wednesday.

State Rep. Mark Dion, D-Portland, first raised constitutional questions about Poliquin’s business activity with Attorney General William Schneider.

Schneider wrote in response that Poliquin should disassociate himself from his businesses and not appear before any governmental bodies on their behalf, but also said there is a lack of clear direction from the courts.

Dion welcomed the opportunity for Democrats to file a brief in the case, which he said would allow them to expand on the questions before the court.

“I expect to work with others to file a brief to fully develop the questions of law regarding Mr. Poliquin’s activities. I believe the court should be fully aware of the factual record that led up to our request for intervention,” Dion said in a statement released by House Democrats on Wednesday, when the court’s letter appeared on the House calendar.

Dion said later that it is unusual for the House to seek an opinion from the Supreme Court, and that it should be unusual.

The Supreme Court is obliged to give its opinion when asked by the governor or either chamber of the Legislature, if the court determines that the matter is important enough.

House Speaker Robert Nutting reiterated Wednesday that the purpose of the request is to clarify the limitations on the state treasurer’s business affairs.

“What I am not interested in is seeing the issue politicized. That’s why the questions the Legislature submitted to the law court are limited to address that part of the Constitution. It’s worth noting that the attorney general’s office and Maine ethics commission have both looked into this and neither concluded that Treasurer Bruce Poliquin should be penalized for his actions,” said Nutting, R-Oakland, in a prepared statement.

Since 1990, the Supreme Court has issued 10 opinions in response to requests from the Legislature or the governor, said Mary Ann Lynch, spokeswoman for the court system. It wasn’t clear how many requests have not drawn opinions from the court.