PROVIDENCE — The Ethics Commission and former Senate President William V. Irons are calling for the state Supreme Court to settle, once and for all, the question of whether the Rhode Island Constitution shields lawmakers from ethics probes into their legislative activities.

Though at odds in the closely watched case to be argued Wednesday, the commission and Irons filed briefs Friday opposing Attorney General Patrick C. Lynch’s argument that the high court need not take up the constitutional question. It would be inconsistent with high-court practice if it did so before addressing a 1999 commission opinion advising Irons that his participation in pharmacy-choice legislation would not be a conflict of interest, Lynch’s office said in a brief filed earlier this month.

John A. Tarantino, Irons’ lawyer, successfully argued in Superior Court last year that the speech-in-debate clause in the Constitution protects other lawmakers from being questioned or prosecuted based on their votes and other legislative actions.

In Friday’s brief, Tarantino says the high court must decide whether the Constitution provides Irons with legislative immunity. If so, then he should not have to defend himself before the commission — period. If the court chooses to weigh the opinion instead of the larger issue, Irons would be forced to put on a defense against ethics charges, he said. “From our perspective, he’s immune.”

The Ethics Commission agrees the court should tackle the constitutional question. To do otherwise would only postpone a decisive ruling on whether state lawmakers are subject to the same code of ethics as every other official in Rhode Island, wrote commission lawyers Jason M. Gramitt and Katherine D’Arezzo.

The record lacks the detail necessary to determine if Irons could have relied on the advisory opinion to clear him of the ethics charges, they wrote. The Ethics Commission, they argued, has yet to decide if Irons omitted or misstated facts in requesting the 1999 opinion.

Irons’ 1999 request did not specify that he was seeking an advisory about drugstore giant CVS, to which he sold an insurance policy. State law says an advisory is binding on future commission proceedings, unless material facts were omitted or misstated by the people requesting the opinion.

Irons unexpectedly resigned from the Senate in 2003 after two decades representing East Providence as a Democrat. Irons had opposed controversial legislation CVS wanted dead that would have allowed patients covered by Blue Cross & Blue Shield to get prescriptions filled at a pharmacy of their choice. It was later disclosed that Irons collected hundreds of thousands of dollars in commissions on a Blue Cross policy covering CVS workers.

The Ethics Commission found probable cause that Irons broke the ethics code. The next step would typically have been a hearing before the commission.

But Irons took the case to Superior Court. Judge Francis J. Darigan Jr. in October sided with Irons and dismissed the ethics charges. The judge found that the speech-in-debate clause shielded lawmakers from being questioned or investigated by the commission based on their legislative acts.

A government watchdog group, meanwhile, took aim at Lynch, whose friend-of-the-court brief came two weeks before arguments.

“The nature of the brief implies to me that the attorney general wants [the Irons case] to go away,” says Robert Arruda, who previously led Operation Clean Government for nine years and brought the ethics complaints against Irons.

Arruda called for Lynch to publicly reveal that he worked as a CVS lobbyist at the same time Irons was considering the pharmacy-choice legislation. He accused Lynch of trying to kill the Irons issue to spare himself bad press as he prepares to run as a Democrat for governor.

Operation Clean Government says it agrees with Arruda that Lynch should have disclosed his role as a lobbyist.

“It really rankles me,” Arruda said. “I think the attorney general should be disclosing that he had an interest at the time.”

Michael J. Healey, spokesman for the attorney general, bristled at the criticism. He could not say whether Lynch had lobbied Irons directly. Lynch was elected attorney general in 2002 and led the first investigation of former Sen. John A. Celona before it became a federal case.

“Apparently, [people] can say whatever they want with The Journal’s blessing,” Healey said. “We have to back up everything we say” with facts.

“[Lynch] has never made an effort to deny that he was a registered lobbyist,” Healey said. He noted that Lynch voluntarily testified before a grand jury probing the State House dealings of CVS. “Our brief did exactly what it is supposed to do. It brought to the court’s attention an issue that hadn’t been raised.”

kmulvane@projo.com