Lighthizer says U.S. is invested in Mexico's success as countries sign trade deal

U.S. Trade Representative Robert Lighthizer stressed that the United States has a stake in Mexico's success as representatives from the United States, Mexico and Canada gathered in Mexico City on Tuesday to sign modifications to the United States-Mexico-Canada Agreement, a new trade pact.

New rules on the origin of steel and aluminum, a key sticking point for Mexico at the end of the negotiations, will go into effect in seven years for steel and in 10 years for aluminum, Mexican Senate Leader Ricardo Monreal said at the ceremony celebrating the signing of the deal.