Donald Trump meets Justin Trudeau in February. The two are at odds over the fate of Nafta.

When Justin Trudeau first met Donald Trump, many highlighted their differences; one had campaigned on protectionism while the other championed trade. And while Trump had blasted Mexicans throughout his campaign to become president, Trudeau had sought out closer relations with the country.

Eight months later Canada’s prime minister is again readying to meet Trump. This time, however, concerns that Trump will follow through on his promises – frombuilding a wall along the country’s southern border to slapping punitive duties on imports – seem like less of a distant possibility.

Chief among the possibilities now being reassessed is Trump’s vow to tear up the decades-old North American Free Trade Agreement (Nafta), the pact that underpins roughly 2.5m Canadian jobs and sees 80% of Mexican exports end up in the US.

“I think there was a lot of tart talk when these negotiations started: getting a win, win, win for all three countries out of this,” said Dan Ujczo, an Ohio-based trade lawyer with Dickinson Wright. “I think the only Ws we’re talking about now is who will withdraw and when.”

Trudeau is slated to meet with Trump on Wednesday. The two-day visit to Washington, which overlaps with the start of the fourth round of Nafta negotiations, suggests that the last round of talks did not go according to plan, said Ujczo.

“I think he wants to sit down and look the president in the eye and see how realistic the prospect of withdrawal is going to be and make the position of the Canadian government known,” he said.

Canadian officials have said Trudeau will use the visit to reinforce how Americans benefit from their relationship with Canada, echoing the message that representatives from Canadian government and business have been spreading as they criss-cross the US in recent months.

From there, Trudeau will head to Mexico City for a two-day visit that will include a meeting with president Enrique Peña Nieto. “And I think the fact that he’s going immediately to Mexico is that he will be reporting back to Mexico,” said Ujczo.

Trudeau’s cross-continent visits come amid concerns that the Nafta talks will collapse. While the teams are working at a breakneck pace, few – including the US trade representative, Robert Lighthizer – seem capable of explaining what is being accomplished and whether negotiations will be able to wrap up by the December deadline. “We’re moving at warp speed but we don’t know whether we’re going to get to a conclusion, that’s the problem,” Lighthizer said last month in Washington. “We’re running very quickly somewhere.”

A months-long delay could hinder the approval process for any new Nafta agreement, as it risks coinciding with the primaries for midterm elections in the US – an overlap that would see the agreement becoming increasingly politicised, said Ujczo.

Another scenario could see a stalemate emerge in the next rounds of talks as negotiators turn their attention to the toughest issues and the full brunt of the Trump administration’s America First policies are laid bare. “It’s going to be very hard for Canada and Mexico to agree to some of these positions,” said Ujczo. “And in my view, this is not a president that has demonstrated a willingness to be very patient and I think in that scenario we would see a withdrawal sometime towards the end of 2017, early 2018.”

The looming threat of withdrawal will force Canada and Mexico into a corner, he said. “The question in Mexico City and in Ottawa will be if they’re willing to take strong US positions in order to save the overall North American free trade agreement.”

Critics say that Mexican officials have long prioritised the preservation of Nafta, seemingly at any cost. Peña Nieto has refrained from responding forcefully to Trump’s insults and Mexico has strayed from its usual foreign policy of non-intervention in other nations’ internal affairs to criticise Venezuela and kick North Korea’s ambassador out of the country – policies that are in line with those of Trump.

Still, senior Mexican officials have mused about the agreement ending, with the foreign minister, Luis Videgaray, noting that such a scenario “is not the end of the world”.

Others are more optimistic, countering that any signal by the White House to withdraw from Nafta would be met with resistance from many American states and American stakeholders. Instead, the three countries will probably emerge with a “thinner” trade agreement that seeks to strike a balance between relations as they now stand and Trump’s demand for greater economic sovereignty, said Dan Ciuriak of the Centre for International Governance Innovation, a Canadian thinktank based in southern Ontario.

“The problem is that this is a negotiation like no other,” he said, pointing to the sharp contrast between the Trump administration’s protectionist agenda and the commitment towards deeper integration that underpins most trade agreements. “You’ve got this duality to the US position, and the two things don’t make sense together.”

Efforts to reconcile this duality have neutered any demands that could compromise sovereignty, such as Canada’s call for a more progressive trade deal that would include chapters on gender and indigenous rights. It’s also left officials hard-pressed to explain what lies ahead for the next two rounds of talks – a realisation that may have prompted Trudeau’s visit to Washington and Mexico City this week.

“The end position is just not clear,” said Ciuriak. “I doubt that anyone right now would be in a position to say: Here is a deal that meets the objectives of all the parties.”