MONTREAL — For three weeks, truckers from across Canada converged on the capital, Ottawa, in protest against coronavirus regulations. They paralyzed the city’s life and disrupted some $300 million a day in trade by blocking crossings to the United States. And they dealt Prime Minister Justin Trudeau one of the biggest crises of his tenure, which ended only when he invoked never before used emergency powers.
Whether his government was right in doing so lies at the heart of a much-anticipated public hearing that began on Thursday, as lawyers for the government and opponents clashed on the government’s use of the sweeping measures last February.
A lawyer for the federal government said that witnesses would outline “the deliberate step-by-step process in which careful consideration was given to all the available options” before Mr. Trudeau invoked the Emergencies Act for the first time in its history.
Lawyers for protest organizers and other opponents, including the leaders of the provinces of Alberta and Saskatchewan, argued that the government was not justified in invoking the Emergencies Act, which granted the authorities extraordinary powers, including seizing protesters’ vehicles and freezing their bank accounts without a court order.
A lawyer for the protesters said that “the government exceeded their jurisdiction both constitutionally and legislatively.”
Mr. Trudeau, ministers and other key actors in the protests are expected to testify at the hearing, which is taking place in Ottawa and is expected to last six weeks.
The public hearing is unfolding in a political context of growing challenges against the federal government’s powers, especially in the provinces of Quebec, Alberta and Saskatchewan. On Tuesday, Danielle Smith, a politician who has pledged to introduce a sovereignty act that would make Alberta “a nation within a nation,” was sworn in as the province’s premier.
The public inquiry, which is being led by a public commission headed by Paul Rouleau, a judge on the Ontario Court of Appeal, is also expected to pore over thousands of high-level documents to determine the circumstances leading up to the government’s use of emergency powers and the basis of its decision.
In addition to assessing the Trudeau government’s decision-making, the commission’s findings are also expected to provide greater clarity on the use of the Emergencies Act, which was created in 1988 to deal with security emergencies as well as natural disasters.
“This is a post-mortem on what occurred, and it might paint the Trudeau government in a terrible light at the end of it,” said Laura Stephenson, a political scientist at Western University. “But what it will also do is really help set the parameters on whether or not other governments would use this act.”
Mr. Trudeau invoked the act after convoy protesters in heavy trucks and other vehicles had forced businesses in Ottawa to shut down for two weeks and paralyzed the capital. It was in effect for nine days.
At the start of their three-week occupation of Ottawa, the truckers appeared to catch the authorities by surprise and were initially allowed to stay. Public anger eventually focused on the handling of the crisis by federal, provincial and local authorities, and forced Ottawa’s police chief to resign for what was perceived as a sluggish response.
The core protesters, part of what they called the “Freedom Convoy,” were angry over federal regulations mandating that truckers crossing into Canada from the United States be vaccinated against the coronavirus. In Ottawa, they drew support on some weekends from thousands of Canadians fed up with government restrictions related to the pandemic. But the protests also drew right-wing extremists and separatists from Western Canada, united in their anti-government grievances.
Mr. Trudeau, a believer in a strong federal government, often provided a visceral target for many of the protesters.
At the hearing on Thursday, lawyers for Saskatchewan and Alberta said that Ottawa’s use of emergency powers had not been justified.
“None of the powers that were created under the federal Emergencies Act were necessary, nor were any of them used in Alberta,” said Mandy England, a lawyer for the Alberta government.
The Canadian Civil Liberties Association, which has sued the government over its use of the act, said that the emergency measures “breached Constitutional rights in a manner that was not reasonable or justified.”
Under the act, a public hearing must be held after its invocation, and the public commission’s report must be handed to Parliament.
As no other prime minister has testified at such a hearing before, experts said it was too soon to say how Mr. Trudeau might be directly challenged, though revelations about the lack of coordination at various government levels could embarrass his government.
Nelson Wiseman, a professor emeritus of political science at the University of Toronto, noted that the hearing is being held as Mr. Trudeau has held office since 2015 and his government has been shaken by several scandals over the years.
“It’s a situation where he won’t control the cards, so there’s always potential downside and not much of an upside,” Mr. Wiseman said. “Trudeau is in a downdraft irrespective of what’s going to happen at the hearing, and this may take him down further.”
