It was an extraordinary day here in Ottawa on Friday. First, the House of Commons voted unanimously to suspend its session until April 20. Then, Prime Minister Justin Trudeau held an outdoor news conference in front of his official residence, with journalists kept at a distance. After his wife, Sophie Grégoire Trudeau, tested positive for coronavirus, Mr. Trudeau, who said he is in full health, has voluntarily isolated himself for two weeks.

The prime minister, members of his cabinet and public health officials both in Ottawa and in several provinces outlined a variety of new restrictions and closings during the day. While everyone accepts that the coronavirus is here and likely to spread, the current hope is to slow the growth rate of infections. The Opinion side of The Times has created an interactive graphic showing how various measures can “flatten” the infection growth curve. It uses the United States as an example, but its principles apply to Canada as well.

The empty schools, theaters, sports venues, libraries and other public facilities across the country raise a big question: How far can the government go? If necessary, can Canada be locked down the way Italy is currently?

To find some answers, I spoke with Steven Hoffman, a professor of global health, law and political science at York University in Toronto.

The federal government’s main tool, he told me, is the Quarantine Act, which was updated in 2005 after the SARS outbreak.