“Government agencies were in possession of significant pieces of information that, taken together, would have led a competent analyst to conclude that Flight 182 was at high risk of being bombed by known Sikh terrorists in June 1985.”Justice John Major, Commission of Inquiry into the Air India Bombing.An intelligence failure is a failure of the imagination, influenced by pre-existing beliefs and various cognitive biases impacting how our minds process incomplete and ambiguous information. Deeply rooted intuitive traps, Groupthink, and misapplied heuristics explain, in part, the inability to accurately measure threats, often with disastrous consequences. Canada's Air India Flight 182 was a supreme intelligence failure, the largest mass murder in our country's history. This is a national catastrophe and disgrace whose true meaning should be understood by all Canadians.Various security experts have stated that the Air India Bombing was Canada's 9/11, but I do not share that opinion. The bombing did not shake our country to the core, induce existential angst, or invite a strong state reaction. Canada's Anti-Terrorism Act came into force two months after 9/11, even though there were no terrorists to prosecute. The one glaring similarity between Air India Flight 182 and 9/11 is how Canada's security infrastructure - like the American equivalent tracking Al Qaeda - underestimated the deadly ambition of the multifaceted threat. Why were the warning signs only brought into sharp focus with the benefit of hindsight and a commission of inquiry almost a quarter-century later?Sikh radicalization was regarded as India's problem. Except for the FLQ, every terrorist entity in Canada before 9/11 had a profoundly international nexus: the Tamil Tigers, Armenian extremism, MeK, and others. This had been the Canadian threat environment for counterterrorism (CT) investigations since the Fenians set up shop in the nineteenth century. They were another country's unwelcome export, violent troublemakers for the RCMP - and, after 1984, the CSIS - to target and monitor. Within this fluid mosaic of secessionist/nationalist threats, Babbar Khalsa emerged, a terror organization calling for the creation of Khalistan in India's Punjab province. These Canadian-Khalistanis represented a significant paradigm shift in CT work: the first extremists to target Canadians in Canada and the scope and number of these threats were rapidly multiplying.On June 22, 1985, two dynamite bombs were checked onto separate flights departing Vancouver. Two months before those fateful check-ins, Talwinder Singh Parmar - a Canadian citizen and architect of this act of nihilistic violence - was communicating with extremists in West Germany, discussing plans to assassinate PM Gandhi on an upcoming visit. This obvious terror plot became the focus of much investigative activity in the lead up to June 23.At Tokyo's Narita Airport, a bomb exploded on June 22, 1985, while the luggage was being transferred to Air India Flight 301. Two baggage handlers were killed, and four others were injured. The explosive was intended to detonate on board the connecting flight, but the terrorists miscalculated the time difference. On June 23, 280 Canadians, including 86 children, lost their lives as Flight 182 crossed the Irish Sea. The next day, the Canadian PM phoned his Indian counterpart to offer condolences. Considering that 280 of the 329 victims were Canadians, it should have been Mr. Gandhi's phone call to make. For the many dedicated CSIS and RCMP employees working Sikh Extremist investigations, the reaction to the bombing was nothing short of shock and devastation.As a CSIS executive manager of CT operations, I accompanied the RCMP Air India Task Force on two of their annual visits to the victims' family members in Montreal, Ottawa, Toronto, and Vancouver, two years after the 2005 acquittal by the BC Supreme Court. It was a humbling experience to be in their presence, sensing their continual disillusionment, grief, anger, and pain. One gentleman shared his account of waiting for his wife and child to arrive at Heathrow, where he would join them for the final leg to India. He watched the flight number marked 'Delayed' on the arrivals board - then nothing. What do you say after hearing this? What bothers me most is how many children were on board that flight from Canada. The school year had just ended, and the summer break had begun. Children lost parents, siblings, cousins, uncles, aunts, and friends. What I recall most from those meetings was the families' stoicism and their expressions of gratitude for not having been forgotten.An Angus Reid poll conducted in 2007 asked Canadians whether they viewed the bombing as a Canadian or Indian tragedy. Of the respondents, only 48% considered it a Canadian event, while 22% viewed it as Indian. (The rest had to think about it). On June 17, 2010, J. Major released a 4,000-page report, chastising successive Canadian governments for treating the relatives of those who died as “adversaries, as if they had somehow brought this calamity upon themselves.” A week later, Canada's PM issued an apology on behalf of the Federal Government. Since that time, memorials have been erected in Montreal, Ottawa, Toronto, and Vancouver. This failure to protect Canadians has yet to penetrate our national consciousness, but it should.Dan Stanton served for thirty-two years in the Canadian Security Intelligence Service. A graduate of Queens University, Mr. Stanton is an instructor in national security at the University of Ottawa Professional Development Institute.