Powerful industry groups and members of Congress support Nafta. Will that political reality limit Mr. Trump’s ability to substantially change or even walk away from the agreement?



The White House is convinced that Mr. Trump has the authority to pull out of Nafta. Legal scholars generally agree, though there are enough skeptics to ensure the decision would end up in court. But Mr. Trump already has backed away from one threat to abandon Nafta after strong opposition from business interests and members of his own party. Corporations and farmers that have benefited from Nafta want to preserve a quarter-century of investment in the development of a continental economy. Changing Nafta would be even more difficult, because it would require congressional approval. Many Democrats share at least some of the president’s concerns about the current deal, but Mr. Trump’s political problems are likely to complicate any White House effort to build a bipartisan coalition.

Since Mr. Trump’s election, the government of Canada has said it welcomes Nafta negotiations and will use them to improve the agreement. Can Canada realistically get improvements or are the talks more about preserving the agreement?

The three nations successfully negotiated improvements to Nafta as part of the Trans-Pacific Partnership. Some of those improvements, like bringing electronic commerce under the deal’s framework, are relatively noncontroversial. Also, Canada and the United States have a shared interest in pushing Mexico to adopt stronger labor and environmental standards. And there are areas, like indigenous rights, where the United States may simply be willing to defer to Canada. Bottom line: It’s easy to imagine upsides. The question is really about the downsides.

If, as Mr. Trump suggested in Phoenix this week, the talks fail and he takes the United States out of Nafta, what will the practical consequences of that be and how is it likely to affect Canada?

Nafta basically added Mexico to the 1989 free-trade deal between Canada and the United States. If the United States pulled out of Nafta, it would be subject to the earlier, substantially similar deal. If Mr. Trump also ends the earlier deal, the two countries would still be subject to the rules of the World Trade Organization. The eventual result could be average import tariffs of about 3.5 percent. Canada and Mexico could choose to maintain Nafta as a bilateral deal or negotiate a new one. But the absence of an agreement between the United States and Mexico would cause problems for Canada. The work of making a given car, for example, is often spread across multiple factories in all three countries — so the Canadian jobs depend on trade between the United States and Mexico. The rise of a continental economy has been painful for many workers in all three countries. There is no particular reason to think that going backward, in whole or in part, would be a less painful process.

For Canada, autos and car parts are a huge chunk of its exports to the United States. And one of the largest automotive employers in the country is Fiat Chrysler, the carmaker that, in recent years, has gone through different owners, a bankruptcy and a bailout that included money from Canada and Ontario.

The turmoil, and the fate of those jobs, continues. Bill Vlasic and Neal Boudette reported this week from Detroit that the company has been actively courting investors and potential partners in China for months. The bad news for Canada: Would-be partners are interested only in Fiat Chrysler’s line of Jeeps and its Ram pickup trucks, neither of which are Canadian-made.