How to kick a diplomat out of Canada

The federal government is under heavy political pressure to expel a foreign diplomat from Canada. Such expulsions are rare — but they do happen.

Earlier this week, the Globe and Mail reported that Zhao Wei, a diplomat at the Chinese consulate in Toronto, was allegedly working on efforts to threaten the family members of Conservative MP Michael Chong.

Chong, whose father was from Hong Kong, has relatives in China. The Chinese Embassy in Canada and Beijing's foreign affairs spokesperson have denied the allegations.

The Conservatives have demanded repeatedly that the Trudeau government explain why it has not yet sent Zhao packing. Foreign Affairs Minister Mélanie Joly said Thursday that the government hasn't made a decision yet.

On Friday, Prime Minister Justin Trudeau would not say whether his government plans to expel Zhao.

"This is a big step, not a small step, to expel diplomats. It's one that has to be taken with due consideration on all the potential impacts and all the very clear messages that it will send," Trudeau said.

"This is something that [Joly] is looking at very carefully, looking at all the information around it, and she will make a decision in due course."

WATCH | Should Canada expel China's diplomat accused of targeting Michael Chong?

The government can expel Zhao at any time — legally, it doesn't even have to offer a reason for the move. It would do so simply by declaring Zhao persona non grata, a Latin phrase meaning "person not welcome."

Canada is a signatory to the 1961 Vienna Convention, a United Nations treaty. Article nine of the convention says that a country "may, at any time and without having to explain its decision, notify the sending State that the head of the mission or any member of the diplomatic staff of the mission is persona non grata."

Canada can also declare a foreign diplomat persona non grata prior to their arrival in this country.

Expulsion is often a country's only option for sanctioning a foreign diplomat. Article 31 of the Vienna Convention grants diplomats immunity from criminal prosecution and in most civil matters while posted to foreign countries.

Canada has expelled diplomats from a number of countries over the years.

In 2018, Canada expelled four Russian diplomats and denied three Russian applications for additional diplomatic staff. Then-foreign affairs minister Chrystia Freeland cited a nerve gas attack on a Russian dissident in the United Kingdom as the reason for the decision. The move was made in concert with several allies.