“The question now is how Mexico and Canada sell this at home — making these unilateral concessions to us — in exchange for nothing.”<br />The talks will be Mr. Trump’s biggest test yet as a deal maker on the international stage,<br />and they could determine how other countries approach the administration in future one-on-one negotiations<br />The language in a letter that Mr. Lighthizer sent to Congress last month giving official notice<br />that the administration planned to renegotiate Nafta strongly echoed the wording used by the Obama administration when it laid out its negotiating objectives for the multicountry T. P.P.<br />Nationalists such as Stephen K. Bannon, Mr. Trump’s chief political strategist,<br />and Peter Navarro, the chief trade adviser, are urging the president to take a more protectionist approach, and officials like Gary D. Cohn, the president’s chief economic adviser, and Steven Mnuchin, the Treasury secretary, are expressing more openness to free trade.