OTTAWA - The federal government faced a constitutional challenge Thursday over its historic invocation of the Emergencies Act, as police began to move on protesters with large trucks paralyzing the heart of the national capital.

Prime Minister Justin Trudeau said using the emergencies law was a measure of last resort to bring an end to the illegal and undemocratic blockades that had harmed Canadians for nearly three weeks.

He made the remarks during debate in the House of Commons over his government's decision to use the law for the first time since its introduction in 1988. The Conservatives accused the prime minister of failing to try to de-escalate the conflict before turning to emergency powers.

Trudeau said using the act was not the first, second or even third choice of the government.

“We did it to protect families and small businesses, to protect jobs and the economy,” the prime minister said. “We did it because the situation could not be dealt with under any other law in Canada.”

Hours later, the federal government was told it would face court action over its decision, as the Canadian Civil Liberties Association announced it was seeking a judicial review of the government's invocation of the act.

The group said at a Toronto news conference it did not want to minimize the effects of the protests across the country, but added it was unclear that the demonstrations endanger the lives, health or safety of Canadians so seriously that they constitute a national emergency.

“The government has brought in an extreme measure that should be reserved for national emergencies, a legal standard that has not been met. Emergency powers cannot and must not be normalized,” said Noa Mendelsohn Aviv, the civil liberties association's executive director.

Police deal with complex law-enforcement issues every day and have cleared multiple border blockades across the country without emergency powers, the association said.

The group's criminal justice director, Abby Deshman, said the Emergencies Act orders do not apply only in Ottawa and actually affect the rights of every Canadian.

The group believes the measures are clearly unconstitutional and it will be asking the courts to step in to defend the rule of law and the constitutional rights of all people across the country, she said.

“Local police across this country have cleared several highly disruptive border blockades and are successfully managing numerous other protesters in communities across the country, all without emergency powers,” Deshman said.

Through the Emergencies Act, new powers have been granted to freeze bank accounts of protest participants and bar people from assembling in specific places or joining protests that threaten trade, critical infrastructure, individuals or property.

It is also now illegal to bring children to within 500 metres of the blockades or provide supplies or property to participants.

The new powers took effect earlier this week but the House of Commons and the Senate must both vote to confirm use of the emergencies law.

The House debate will continue through the weekend and Monday with a vote planned for 8 p.m. ET that day. If the motion fails, the act will be suspended immediately.

The Senate will begin debating the motion Friday and at some point hold its own vote.

Trudeau said the act is not prohibiting lawful protest, including by those who disagree with the government's management of the COVID-19 pandemic, but he said these blockades are illegal and partly funded by foreign nationals, and threaten Canada's economy, its trading relationships and public safety.

Deputy Prime Minister Chrystia Freeland said at a news conference bank accounts had already been frozen and more will be put on hold in the coming days. But she refused to say how many, or even declare if accounts could be frozen for people who aren't participating in the blockade but who donated to the convoy's various online fundraisers.

The Emergencies Act was passed in 1988 to replace the War Measures Act, which had been used to suspend civil liberties during both of the world wars and the 1970 October Crisis. The new act has more checks and balances than the previous one, including parliamentary oversight and a requirement to respect the Charter of Rights and Freedoms.

Interim Conservative Leader Candice Bergen said her party does not support use of the act because the government has not proven the demonstrations pose a serious threat to Canada's sovereignty, security or territorial integrity and couldn't be dealt with under existing laws.

“The prime minister is doing this to save his own political skin,” she said. “But Mr. Speaker, this is not a game. It comes at the cost to Canadians' rights and freedoms.”

Bergen said many of those in the protest are neighbours, constituents and Canadians who just want to be heard and “given even just a little respect” by Trudeau.

She repeated her allegation that Trudeau himself was to blame for raising the temperature of the convoy by refusing to meet with them and accused the prime minister of hiding for the first week of the blockade.

That prompted Green MP Elizabeth May to counter that Trudeau wasn't hiding - he had COVID-19 and was in isolation.

Bergen, who took over as interim leader Feb. 2 following a caucus vote against Erin O'Toole, supported the demonstration in the early days, posing for photos with participants and dining with some of them at a restaurant in Ottawa. She said reports of hateful symbols and harassing behaviour were the exception within the crowd, not the norm, and asked Trudeau to extend an “olive branch” out to the demonstrators in a bid to end the impasse.

The Conservatives also pushed a motion asking the government for a timeline to end federal pandemic restrictions and mandates, but the motion failed when the Liberals and NDP voted against it.

As the Ottawa blockade stretched into its second week, Bergen said it was time for the convoy to go home because protesters had been heard.

On Thursday, Bergen also turned her criticism on NDP Leader Jagmeet Singh. Singh said his party will reluctantly support the use of the act because the blockades are a national crisis, even though the NDP is critical of Trudeau for allowing things to get this far.

Bergen said “history will not be kind to the leader of the NDP or his members on this particular question.”

Singh pushed back at Bergen for supporting the convoy at any point, when it is “no secret that the goal of this convoy, posted brazenly on their website, reiterated as recently as earlier this week in a press conference, was to overthrow a democratically elected government.”

“The interim leader of the Conservative Party, says, 'We have heard you, we will keep standing up for you.' Do you regret endorsing a convoy that is attacking the fundamental democracy of our country? Do you regret endorsing and supporting an occupation that has harassed citizens?”

Liberal MP Yasir Naqvi, whose Ottawa Centre riding includes Parliament Hill and downtown Ottawa, said his community “has been held hostage” by demonstrations that are not peaceful. He asked whether MPs who had supported the convoy and encouraged protesters to keep honking would tolerate demonstrators in their ridings, harassing their constituents.

This report by The Canadian Press was first published Feb. 17, 2022.