Scandalized politicians demanded a role in watching the watchers — and they got it.
Canadian parliamentarians still don't have that role, as noted in recent weeks.
With the country now debating an anti-terror bill that would give intelligence agencies more power, four ex-prime ministers have called for new democratic scrutiny. U.S. whistleblower Edward Snowden also weighed in, saying Canada has one of the weakest spy-monitoring systems in the western world.
American experts say their system isn't perfect either. But as one pointed out, there's no nostalgia for the old days before the modern system that allowed legislators to scrutinize the spies.
"I can't imagine a scenario where we would go back to not having congressional intelligence committees doing oversight," said Carrie Cordero, a former federal official and current director of national security studies at Georgetown University.
"It does provide, I think, a level of comfort and a level of legitimacy that there isn't one branch (of government) doing its own thing."
The current debate in Canada is a bit like the one Americans had in the 1970s with a notable exception: theirs was infinitely more sensational.
It began in the wake of the Watergate scandal, when the CIA commissioned an internal review of illicit activities that included political espionage at home and political assassinations abroad.
In December 1974, a New York Times story by Seymour Hersh catalogued the agency's use of break-ins, wiretapping, and the illegal opening of mail while snooping on political opponents, suspected political opponents and journalists.
The Senate and House convened their own investigations within weeks. Their 1975-76 reports described at least eight assassination plots against Fidel Castro alone.
The CIA engaged in plots to kill the Cuban leader with poison pills, a poison pen, deadly bacterial powder and a high-powered rifle. It nearly carried out a plan with the Italian Mafia to have a young woman lure Castro into sharing a drink that would have proven to be the quintessential last call.
It also worked on non-lethal schemes like spiking cigars with a hallucinogen to get Castro high before a speech, or dusting his shoes with thallium to make the bearded revolutionary lose his iconic whiskers.
The stories were bloodier in Congo, Chile, Vietnam and the Dominican Republic. The Senate report described varying levels of CIA interaction with groups that carried out killings there.
Less than a month after the release of the so-called Church report, the Senate Select Committee on Intelligence was born.
Its 15 members include representatives from both parties, senior members of the chamber, and a range of expertise on budgeting, defence, justice and foreign relations. The House set up a similar committee the following year.
Now politicians from different parties approve the intelligence budget, and they have access to details of agencies' inner workings and ongoing operations. That new power was codified in a law that says Congress must be kept "fully and currently informed" of U.S. intelligence activities.
One critic says the system has deficiencies: it's not enforced with criminal penalties for non-disclosure, and there's no agreement on the definition of what it means to be "fully" or "currently" informed.
"The first question is — has (oversight) happened since the 1970s? And then, if it happened, was it useful?" says Kathleen Clark of the Washington University School of Law.
Her research points to different cases where the answer was no.
In 1986, members of Congress only learned about the sale of arms to Iran 10 months later, after a Lebanese newspaper reported details of what became the Iran-Contra affair.
In 2002, members of Congress were invited to a room to read 92 pages of intelligence on Iraq — but they were prevented from bringing staff who might have helped lawmakers scrutinize the findings.
She's scathing about Congress's silence over post-9-11 surveillance programs. She said members meekly asked for permission to brief staff; only raised their concerns publicly in a vague way; and didn't use their parliamentary immunity to speak more bluntly on the congressional floor.
That meekness, she said, created the conditions for a whistleblower like Snowden.
But her research also documents power that opposition lawmakers have in the U.S. — power that doesn't quite exist in Canadian democracy.
In the 1980s, when news reports revealed that the CIA had engaged in covert action to mine Nicaragua's harbours, she said the Senate committee complained that it hadn't been informed and Congress cut off financing for the Nicaraguan Contra rebels. And after a years-long fight, the Senate committee recently released a report on post-9-11 torture.
Canada's public safety minister defends the Canadian model — which involves the federal cabinet picking citizens to serve on review boards for different agencies.
"If you look at other countries, we've seen that their models didn't prevent leaks and misbehaviour," Steven Blaney said.
"So why would we borrow other models that have proven to have weaknesses and flaws when we have an excellent Canadian model?"
Parliamentary review isn't an American thing — it's a normal thing in most countries, said Craig Forcese, vice dean of law at the University of Ottawa.
"What we have almost everywhere except Canada now, in democracies, is parliamentary review," Forcese said.
He recommends a body that can assess the work of all agencies, unlike the current system where a hodgepodge of citizen bodies work in silos and don't communicate.
"No one's got a picture of the forest (now). Everyone focuses on their individual tree."