Justin Trudeau is accusing the Conservative government of adopting immigration policies toward Muslims akin to the Second World War policies restricting Jews' entry into Canada.

His harsh criticism was part of his speech, "Canadian Liberty and the Politics of Fear," which he delivered Monday night in Toronto to about 500 McGill University alumni.

"So we should all shudder to hear the same rhetoric that led to a 'none is too many' immigration policy toward Jews in the '30s and '40s being used today, to raise fears against Muslims today," he said.

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The "none is too many" reference is to the title of the book by Irving Abella and Harold Troper. It was written several decades ago and argues that Canada was one of the most resistant countries in the Western world to saving Jews from Europe.

His linking of the plight of Jews then to Muslims now forms part of his attack on the federal Conservatives for distorting the rights and freedoms of Canadians.

The remarks come just a month after he announced his support for the most sweeping changes to security legislation since the Sept. 11, 2001, attacks and as MPs prepare for three days of hearings this week on the Conservatives' new legislation – Bill C-51, also known as the Anti-Terrorism Act (2015). Critics have condemned it for restricting Canadians' freedoms. It will strengthen the powers of the RCMP and the Canadian Security Intelligence Service and criminalize the promotion of terrorism.

"Conservatives pretend to talk a good game about freedom, but look at what they have done with it," Mr. Trudeau said. "They have fallen a long way from the era of Sir John A. Macdonald to the 'why do you hate freedom?' taunts of the recently departed Sun News Network."

Stephen Lecce, spokesman for the Prime Minister's Office, issued a statement in response. "Through the Anti-Terrorism Act 2015, we are taking decisive action to thwart efforts to use Canada as a recruiting ground, prevent terrorism travel and attacks on our soil," he said.

Mr. Trudeau made only a fleeting reference to the new bill, which he has said his party will support but will try to amend if it forms a government. The Official Opposition NDP is opposed to the legislation.

Mr. Trudeau said "… our social contract sometimes requires us to moderate our freedoms in order to ensure we maintain them in the long run."

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"The ongoing question for democracies is how we strike the right balance."

He did not offer any specifics about how he would amend the legislation to reflect that balance. Rather, he said these questions will be answered in his party's national security policy in its election platform. An election is expected in the fall. Polls show the bill is extremely popular among Canadians, especially in Quebec.

The Tories introduced it after the deaths of the two soldiers – one in Quebec and one in Ottawa – last October, which they quickly labelled as terrorist attacks.

Mr. Trudeau has been criticized by Conservatives and fellow Liberals alike for being weak on the security file. He voted against sending Canadian fighter jets to Iraq and made an off-colour remark about providing humanitarian aid rather than "whip out our CF-18s and show them how big they are." Senior Liberals argued for a Canadian combat mission to fight the Islamic State.

Meanwhile, in his speech, Mr. Trudeau characterizes the Conservatives' approach to politics as "corrosive."

"It stokes anxiety and foments fear," he said. "Instead of encouraging Canadians to fight for one another's liberty, it tells us to be suspicious of each other's choices."

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And he warned against blurring the line "between a real security threat and simple prejudice."

"In defending Canada, we cannot allow ourselves to become less Canadian."

Mr. Trudeau talked also about the Muslim woman from Quebec, Rania El-Alloul, who wore a head scarf to court. The judge refused to hear her case unless she removed her hijab.

"Rania's story is part of a troubling trend that Mr. Harper seems keen to accelerate and exploit," said Mr. Trudeau, noting that the Conservatives' policy declaring that women cannot wear a niqab during citizenship ceremonies was overturned by the Federal Court of Appeal.