The chief Nafta negotiator for Mexico’s president-elect said that the continuance of U.S. tariffs on the nation’s steel exports at the signing of a new trade deal is regrettable and he hopes they’ll be lifted by the end of this year.

Speaking the night before the nations and Canada are set to sign the successor to Nafta, Jesus Seade predicted a tough road to approval in U.S. Congress, suggesting it may take a full year. The nations will need to find ways to satisfy Democratic concerns about enforcement rules, given the party’s incoming majority in the House of Representatives, Seade said in an interview with Bloomberg Television on Thursday.

The governments of Mexican President Enrique Pena Nieto and Canadian Prime Minister Justin Trudeau were aiming to get Donald Trump to lift the steel tariffs before signing the accord, known as the U.S. Mexico Canada Agreement, on the sidelines of a Group of 20 meeting in Argentina. That effort looks to have fallen short, and for Mexico talks will now pass to incoming President Andres Manuel Lopez Obrador, who takes office Saturday.

The steel tariffs “cannot be there for an extended period,” Seade, who is set to become undersecretary for North America in Lopez Obrador’s Foreign Ministry, said in Buenos Aires. Elimination of the duties within “the calendar year would be very natural, because it’s fully discussed. That’s my hope.”

The USMCA trade pact would update the 1994 North American Free Trade Agreement between the countries, which trade more than $1 trillion annually. It requires approval by legislators in all three nations. Canada struck a deal with the U.S. in September to avoid America and Mexico proceeding without the country after they came to their own agreement in August. The pact overhauls rules affecting wide swaths of the economy—including a requirement for more high-wage content in auto manufacturing.

Asked about the crisis on Mexico’s border with California, where American officials hit demonstrating Central American migrants with tear gas this week, sending men, women and children fleeing and choking, Seade downplayed the possibility of stepped-up Mexican deportations.

“We don’t deport; that’s not something that’s part of our traditions or practice,” Seade said. “Really my part in this story is to look beyond the current crisis and build a relationship where we address the migration issue at the root, bringing development to the regions where migration comes from in Mexico and particularly in Central America.”