Canada has blamed the Indian government over the assassination of a Sikh leader in British Columbia in June, sparking a diplomatic crisis between the two countries and confronting the Biden administration with a difficult choice.

"Over the past number of weeks, Canadian security agencies have been actively pursuing credible allegations of a potential link between agents of the government of India and the killing of a Canadian citizen," said Canadian Prime Minister Justin Trudeau in Parliament on Monday.

"Canada has declared its deep concerns to the top intelligence and security officials of the Indian government,” he added. “Last week at the G20 I brought them personally and directly to Prime Minister Modi in no uncertain terms."

India’s Ministry of External Affairs denounced the allegations as “absurd and motivated,” accusing Canada of harboring “Khalistani terrorists and extremists” who “continue to threaten India’s sovereignty and territorial integrity.” New Delhi expelled a Canadian diplomat on Tuesday in a tit for tat response to Canada’s expulsion of an Indian diplomat the day before.

The victim, Hardeep Singh Nijjar, was a leading proponent of the Khalistan movement for the establishment of an independent Sikh state in India’s northern Punjab region. His ethno-religious separatist activism did not earn him many friends in the Modi administration, with the Indian government accusing him in 2018 of being involved in multiple targeted killings.

“From the vantage point of India, he is a terrorist… the very fact that this guy had extreme political preferences, in the mind of the Indian government, would make him not only an extremist but a terrorist,” Max Abrahms, Associate Professor of Political Science and Public Policy at Northeastern University and leading terrorism expert, told Responsible Statecraft. “Clearly India views his political preferences — an independent Khalistan — as extreme and also as ipso facto evidence of supporting terrorism…”

The Khalistan issue has loomed over Canada-India relations for years. Canada, home to the largest Sikh community in the world, has been the site of previous Sikh-led protests that have invited sharp rebuke from Indian officials. New Delhi criticized the Canadian government for turning a blind eye to what it described as the “extremist” activities of Khalistan movement activists with Modi expressing concerns over previous Sikh protests to Trudeau on the sidelines of the G20 summit earlier this month.

“They are promoting secessionism and inciting violence against Indian diplomats, damaging diplomatic premises and threatening the Indian community in Canada and their places of worship,” the Indian government said in a statement at the time.

The two sides have frozen negotiations over a proposed trade deal that both countries hoped would be finalized by the end of the year, with Indian officials reportedly citing “certain political developments.”

Beyond the ongoing fallout between Ottawa and New Delhi, Trudeau’s Tuesday remarks have put many of Canada’s closest allies in a difficult spot. On the one hand, the White House has made it a top strategic priority to court India amid its intensifying standoff with China. On the other hand, the Biden administration has built its foreign policy brand on the importance of marching in lockstep with its Atlantic partners — failing to publicly back Canada could deal at least a symbolic setback to the Biden administration’s grand vision of a united Atlantic front.

“The United States deeply values the bilateral relationship with India and has invested substantially in this relationship, evidenced most recently by the very public hosting of Modi at the White House as well as the very high-profile one-on-one meeting between Biden and Modi at the G20 a few weeks ago,” said Abrahms.

“Washington deeply values and is investing in this relationship and, therefore, I find it very unlikely that Biden will interject himself in a way that will create any meaningful friction with the development of relations with India, which are seen as essential in terms of containing China as well as taking a leadership stance in the global south,” he continued, adding that U.S.-China trade ties and a desire not to alienate the domestic Indian vote could also be salient factors for the administration.

Abrahms noted that the potential costs of not backing Canada are outweighed by the dangers of confronting India because New Delhi, unlike Ottawa is a geopolitical pivot player. “Canada doesn’t have the option of moving away from the United States, nor would it want to, whereas with India, one of the reasons why we’re courting it so much is because it has a history of independent foreign policy during the Cold War with respect to the Soviet Union,” he said, adding that that Washington cannot take for granted New Delhi’s support against Beijing.

“It’s not entirely clear that India will be the ally that the United States wants against China in the Indo-Pacific, so the U.S. is doing this charm offensive not just because India is rightfully seen as important but because, without it, there could be a real risk that India won’t be the kind of ally that we need in any future direct conflict with China.”

Asked if the White House could possibly sanction the Modi government over Trudeau’s assassination claims, Abrahms said he would be surprised even by “just a rhetorical dressing-down of India.”

It is an open question how Canada’s leadership would respond if Washington does, in fact, choose to stand aside. Canadian Foreign Minister Mélanie Joly parsed the assassination claim more delicately than Trudeau, referring to the incident as an “allegation” that would constitute a “grave violation” of Canada’s sovereignty “if proven true."

It appears the door has been left ajar for de-escalation — how Ottawa chooses to proceed, and the full extent of the damage that the Khalistan assassination row will do to the Canada-India relationship, remains to be seen.