The foreign interference inquiry starts today with a big question — how much must it keep secret?

The independent inquiry into foreign electoral interference begins public hearings today. Its first item of business is working out what it can — and can't — talk about publicly.

The inquiry — officially the "Public Inquiry into Foreign Interference in Federal Electoral Processes and Democratic Institutions" — was triggered by media reports last year which, citing unnamed security sources and classified documents, accused China of interfering in the 2019 and 2021 federal elections.

Commissioner Justice Marie-Josée Hogue has been asked to investigate the extent to which China, Russia and other nations interfered in those elections, and how information about foreign interference flowed within the federal government. Just last week, the commission asked Prime Minister Justin Trudeau's government to share information about possible meddling in elections by India.

But before the inquiry team can dig into the core issues, it first needs to decide how it can share national security information with the public when classified documents and sources are involved.

The preliminary hearings, which run Monday to Friday, will probe "the challenges, limitations and potential adverse impacts associated with the disclosure of classified national security information and intelligence to the public."

"This is one of the biggest challenges that the Commission will face," Hogue said in a media statement last week.

The inquiry will hear this week from Canadian Security Intelligence Service (CSIS) Director David Vigneault and Public Safety Minister Dominic LeBlanc, along with national security lawyers.

Stephanie Carvin, a professor of international relations at Carleton University and a former national security analyst with CSIS, said the first week will be all about setting ground rules for dealing with sensitive issues and testimony.

Despite some of the legal barriers surrounding classified information, she said, CSIS has an opportunity here to be more candid with Canadians about the threat.

"This is a very big public forum to make a very definitive statement about the situation in Canada. There is an opportunity here for the service to put its case forward," she said.

"Whether or not the service will take the opportunity to do so is questionable. They're not comfortable in these environments, just to put it mildly."

Through March, the commission will address the extent to which foreign interference occurred in past elections.

Carvin said Hogue has to create an environment where victims of foreign interference feel they can come forward without facing retaliation. CSIS says Chinese government officials have sought to threaten and intimidate Chinese Canadians and permanent residents to keep them from cooperating with the commission.

"My hope is that the victims will be heard," said Carvin. "For too long, we've looked at foreign interference as a non-Canadian problem. We've looked at this as an overseas problem, or as an issue that doesn't impact Canadians. But these are our neighbours."