Seventy years ago, David Shugar was wrongly accused of being a communist — of spying on behalf of the Soviet Union — by the Canadian government.

Shugar, who was working for the federal health department in Montreal at the time, was secretly detained and interrogated for four weeks without counsel — a Kafkaesque ordeal some experts warn will be possible again under the Conservative government’s controversial Bill C-51.

“There are parallels between what happened to Shugar and what is happening today,” York University professor emeritus Reg Whitaker told iPolitics.

NDP MP and public safety critic Randall Garrison agrees. He said detention has a much lower legal threshold than an arrest and those who are detained don’t have access to legal counsel.

“We asked in the Public Safety committee for an addition to the Conservatives’ third amendment that would have said CSIS has no power to detain any person or transfer any person to any other state and the Conservatives voted against that so it leaves the possibility open that secret detentions are possible – they’re not ruled out in this bill in any way,” said Garrison.

Despite the courts finding that Shugar was innocent, newspapers and officials described him as a communist spy. He took a position at a university in Poland, where he’s lived for the past 63 years. Shugar, 99, recently described his ordeal to the Montreal Gazette as a “nightmare,” and his niece, Harriet Shugar, launched a campaign demanding an apology from the Canadian government.

Shugar’s ordeal unfolded between the high-security environment of World War II and the paranoia of the Cold War; a context echoed in the current international war against Islamic State terrorists and what has been criticized as inflammatory political rhetoric directed at Muslim-Canadians.

Whitaker said that the powers CSIS would have under Bill C-51 are “scary” for the very fact that CSIS could secretly detain suspects, like Shugar, without the safeguard of legal counsel.

“We should look at the lessons of the past and realize that innocent people can get badly bruised as a result of those kinds of arbitrary state actions — C-51 has a whole lot of things in it that are pretty alarming from a civil liberties point of view.”

Whether CSIS would exercise this power is another matter, said Whitaker, but the possibility is there.

“The War Measures Act, under which Shugar was detained – has now been repealed,” noted Whitaker. It was replaced with the Emergencies Act, which Whitaker described as measured and “much better.” But C-51 brings us back to the past, he warned.

“We’re emerging from that past, and here we are possibly writing a law that would allow and return to secret detentions – as was done to Shugar,” said Whitaker.