There's no reason why the secretive all-party Board of Internal Economy couldn't lift the curtain on its ongoing investigation into NDP spending, according to former House Law Clerk Rob Walsh.

On Wednesday, the House rebuffed a New Democrat-backed motion that would have ordered the Board to hold all future meetings in public. The move failed to gain the required unanimous consent to be put to a vote. 

Although the Liberals didn't oppose the motion, party staffers argued that such a change can only be done through an amendment to the Parliament of Canada Act, which is exactly what party leader Justin Trudeau is proposing in his just-tabled private members bill.

In response to a tweeted query, however, Walsh, who retired from the Chamber in 2012, pointed out that nothing in the Parliament of Canada Act says the Board has to meet behind closed doors.

He also noted that, as it is "a creature of statute," he noted, its decisions may also be subject to judicial review — and, as it is not a parliamentary committee, privilege may not apply to those proceedings.

That could make MPs reluctant to go public with any discussion that could potentially spark a legal challenge.

The Board already has the power to establish by-laws on both "the calling of meetings" and the "conduct of business at those meetings." 

Secrecy oath may not bind Board as a whole

In a brief exchange with reporters outside Thursday's closed-door session, however, Liberal MP Dominic LeBlanc defended the decision to remain in camera.

He cited the secrecy oath sworn by all Board members, in which they pledge not to reveal Board-related business to any person "without due authority."

That, according to his party, at least, means the Board deliberations must remain off the public record, at least for now. 

Liberals have also pointed out that the oath includes a specific reference to information related to investigations, which, in their view, could put Board members at risk of being sued personally if such details were revealed.

If passed, Trudeau's bill would explicitly permit meetings related to ongoing investigations to take place in public, and would also rewrite the oath to apply only to matters discussed behind closed doors.

Walsh, however, suggested the Board may have already have the power to give its members the "due authority" required to set aside the confidentiality provisions of the oath.

"There's nothing in [the Act] that says [the] Board can't meet in public," he tweeted.

The oath, he said, has limited application.

"It allows [the] BOIE to prevent disclosure of information it wants to keep secret, but it can allow disclosure of any information," he explained.

Given that interpretation, he said, it's his opinion that the oath taken by individual MPs "is not binding on the Board as a whole."

That may be just what the New Democrats needed to hear to take another crack at forcing the Board's current activities into the public eye.

The Liberals, however, appear to be as yet unpersuaded by Walsh's arguments.

"We feel that BOIE should be open, which is why we supported the NDP's [unanimous consent motion] yesterday, but it's not clear how any MP would get around the statutory oath of secrecy," party spokeswoman Kate Purchase told CBC News. 

"That's why we feel that it is important to do this in the proper manner and change the law through Mr. Trudeau's private members' bill to make the Board open by default."