When Prime Minister Justin Trudeau of Canada accused the Indian government in September of being behind the killing of a Canadian Sikh activist near Vancouver, there was fierce denial, skepticism and muted support.
India vehemently denied the accusations and forced out 41 Canadian diplomats. Canada’s allies, including the United States, said little, concerned about offending an increasingly important counterweight to China and Russia.
Even Canada’s opposition leader demanded that Mr. Trudeau “come clean” with the evidence behind the accusations.
But Canada’s case against India and Mr. Trudeau’s lonely stand were shored up on Wednesday after federal prosecutors in Manhattan revealed details of what they said was a separate plot in the United States, with links to the killing in Canada.
“The news coming out of the United States further underscores what we’ve been talking about from the very beginning, which is that India needs to take this seriously, the Indian government needs to work with us to ensure that we’re getting to the bottom of this,” Mr. Trudeau told reporters on Wednesday.
According to a federal indictment filed Wednesday in Manhattan, an Indian national was charged in an assassination plot organized by an Indian government official who was also involved in the June killing of the Canadian Sikh separatist near Vancouver, Hardeep Singh Nijjar.
In the New York case, the Indian national, Nikhil Gupta, tried to arrange the ultimately unsuccessful killing of a prominent American Sikh separatist in New York at the Indian government official’s direction, according to the indictment.
Both Mr. Nijjar and the New York leader — identified as Gurpatwant Singh Pannun, the general counsel for the New York-based group Sikhs for Justice — were well-known in the Sikh diaspora as advocates for a Sikh homeland to be carved out of the Indian state of Punjab. The Indian government labeled both men as terrorists in 2020.
“With the United States coming out with all this new information, it validates Canada’s position,” said Aaron Ettinger, an expert on Canadian foreign policy and U.S.-Canada relations at Carleton University. “You could sense the righteousness in Trudeau’s voice when he came out to speak.”
In June, Mr. Nijjar, the leader of the Vancouver area’s most important Sikh temple, was gunned down in a violent, professional-style killing outside the temple. As Mr. Nijjar was leaving the temple inside his pickup truck, a white vehicle blocked him, and two hooded men sprayed Mr. Nijjar with automatic gunfire, according to witnesses.
Hours after the killing, according to the indictment filed on Wednesday, the Indian government official sent Mr. Gupta “a video clip that showed Nijjar’s bloody body slumped in his vehicle.” The next day, Mr. Gupta is heard referring to Mr. Nijjar as “#4, #3” on a list of assassination targets in Canada and the United States.
Mr. Trudeau accused the Indian government of involvement in Mr. Nijjar’s killing in Parliament, saying that the accusations were based on intelligence, but declining to provide details. India described the accusations as absurd and called Canada a haven for Sikh separatists.
“There were persistent questions about why wasn’t more evidence forthcoming,” said Sanjay Ruparelia, a political scientist and expert on India at Toronto Metropolitan University.
The charges in the United States, he added, “bolsters Trudeau’s credibility. He made a very unusual and audacious move in September to make these allegations himself, as the prime minister, in the House of Commons.”
But if the case in New York boosted the credibility of Canada and its leader, it also exposed the fragility of Canada’s foreign policy and its diminished role in the world set against the rise of countries like India and China, experts said.
Even as Canada’s relations with India have deteriorated over Mr. Nijjar’s killing, tensions with China have increased over mounting evidence of the Chinese government’s interference in Canadian politics.
Following the indictment in New York, the Indian government said it would form a “high-level” committee “to look into all the relevant aspects of the matter.”
The reaction was notably different from India’s reaction to Mr. Trudeau’s accusations, experts said.
“The difference was striking,” Mr. Ruparelia said. “In the case of the Canadian allegations, the Indian government dismissed them as absurd and motivated. India retaliated by suspending visa services and forcing Canada to withdraw its diplomats from New Delhi. That just underscores the importance that Washington has vis-à-vis Ottawa.”
The Indian government’s response showed the shifting place of a medium Western power like Canada in a world that is being reshaped by other more muscular nations, experts said.
“Relative to the 20th century, Canada’s place in the world has diminished considerably,” Mr. Ettinger said. “It no longer has the kind of sway that Canadians once imagined Canada had. Foreign powers clearly see Canada as being of secondary consideration.”
Canada has also failed to forge strong ties with India that could have defused the recent crisis, Mr. Ettinger said. Canada, he said, has mainly regarded India in economic terms rather than as a key geopolitical ally.
“India, as a postcolonial country, wants its own strategic autonomy,” Mr. Ettinger said, “and Canada really has only seen it as an export market. So we’re really speaking past each other.”
