Canada will have to adapt and keep its eye on the future when U.S. President Donald Trump rolls out his strategy for re-worked North American trade, according to former Prime Minister Brian Mulroney.

Mulroney told BNN on Tuesday that Canada has to be ready when Trump finally unveils his foreign trade plan but stressed that we’re still lacking details on the president’s strategy.

“Eventually we’ll know what their agenda is. Some of it, I think, will be bilateral and some of it will be trilateral,” Mulroney said in an interview, noting that there are still factors including the Senate confirmation of Commerce Secretary Nominee Wilbur Ross to be completed before any policy gets put into place.

“The only thing that could change [a mix of bilateral and multilateral deals] is if the president of the United States articulated a brand new foreign trade policy, in which he said, ‘We will never again sign a trilateral or multi-lateral agreement. We’ll only sign bilateral deals.’

Then we’d all have to look at it, because then what he’d be saying is, ‘If you want access to our markets, we’re only going to deal with you on a bilateral basis.’”

There’s a difference, according to Mulroney, between such a policy shift and the “appalling” idea of Trump throwing Mexico under the bus when it comes time to unroll his new or ‘tweaked’ North American trade pact.

Mulroney said shifting to an exclusively bilateral trade policy “wouldn’t be throwing someone under the bus,” adding “I think that’s an appalling thing for a political leader to do, under any circumstance.”

Trump praised the U.S. strong trade relationship with Canada when Prime Minister Justin Trudeau visited the White House last Monday.

"We have a very outstanding trade relationship with Canada,” he said at a joint press conference with Trudeau. “We'll be tweaking it; we'll be doing certain things that are going to benefit both of our countries," Trump said

However, the former PM still expects Trump to go ahead with his headline-grabbing Mexican border wall, a campaign promise Mulroney says is “unrelated to NAFTA.”

“That’s his signature issue: The wall. So if he went back to the people not having done anything there, I think he’d have a political problem,” Mulroney told BNN. “That’s a bilateral issue between Mexico and the United States that has nothing to do with NAFTA. NAFTA doesn’t cover immigration or things like that, or wall-building. It’s job-creating, exchange of investment and trade.”

Mulroney signed NAFTA into action in 1992 alongside then-U.S. President George H.W. Bush and Mexican President Carlos Salinas and negotiated its predecessor – the Canada–United States Free Trade Agreement – with former U.S. President Ronald Reagan.

He cautioned today’s leaders, including Prime Minister Justin Trudeau, to think about the future and factor in globalization when making changes to existing agreements.

“If you’re going to be a leader, as I’ve said, you can’t think about easy headlines in 10 days. You’ve got to think about a better Canada in 10 years,” he said. “And you’ve got to [make] decisions, unpopular though they may be now, to benefit Canada 20-25 years later.”