Legislative leaders voted Wednesday to sue Attorney General Sean Reyes to force release of a legal opinion they requested about whether Gov. Gary Herbert overstepped his legal powers in setting rules for the 3rd Congressional District special election.

The Legislative Management Committee — consisting of top leaders from both parties and chambers — unanimously approved the move in a special meeting, but only if Reyes chooses in coming days to continue withholding the document.

Senate President Wayne Niederhauser said the offices of Reyes and Herbert contacted legislative leaders on Wednesday — a day after they announced they may pursue a lawsuit — and have “begun communications” that may lead to release of the document.

“We all would like to resolve this without conflict,” Niederhauser said. However, “We are going to insist that our legislative prerogative is protected.”

Also, leaders said they could drop the suit if Reyes turns the opinion over to The Salt Lake Tribune, as ordered last week by the State Records Committee.

That panel found that the legal opinion was rightly protected as a “draft” document, but then ruled 6-0 that the public interest in its disclosure outweighed any privacy interest. The attorney general’s office hasn’t said whether it will appeal, but the governor is openly pushing it to go to court.

Legislative leaders earlier talked about the possibility of joining The Tribune in any legal battle it may pursue, but made clear on Wednesday they are now aiming to file their own lawsuit using different legal arguments.

John Fellows, the Legislature’s general counsel, said state law requires the attorney general to prepare and provide opinions to the Legislature upon request — and said Reyes is violating that statute.

The Legislature requested such an opinion when Herbert contended he had power not only to call a special election to replace retiring Rep. Jason Chaffetz, but to order the detailed procedures and deadlines necessary — because the law was silent on them. Lawmakers wanted Herbert to call them into special session to adopt such rules, but he refused.

House Speaker Greg Hughes reiterated was he has said previously — that the legal opinion was ready for delivery to the Legislature when the governor intervened.

“It is our understanding that the attorney general’s office completed the opinion, it was signed, and ready for delivery. Because the governor’s office objected to release of the opinion, the attorney general has not yet provided the Legislature with the legal opinion.”

The Legislature delayed a lawsuit until now not wanting to interfere with the special election, so that the 3rd District vacancy could be filled as soon as possible.

Dan Burton, spokesman for Reyes, said the attorney general “welcomes the opportunity for clarity” that a lawsuit by the Legislature may bring.

“There has not been an ethical path forward for the attorney general. The opportunity to clarify through the courts … or legislation will allow us to see what we can do or not do.”

Reyes chose not to deliver the document because of ethical concerns, his office said.

The attorney general’s office said it, along with Herbert’s lawyer, approached the Utah State Bar and said they were told there was a 50-50 chance of a conflict of interest because the attorney general is constitutionally bound to advise the governor. So Reyes chose not to release the opinion.

Niederhauser said no conflict occurred because the attorney general’s office used an “ethics wall” with separate lawyers doing separate work for the governor and Legislature. He said other legal firms often use that procedure to avoid a conflict of interest.