The president signed executive orders today offering a monthlong exemption, until April 2, for all goods covered under the U.S.-Mexico-Canada trade agreement, which includes most U.S. imports from those countries. About 10 percent of Mexico’s exports to the U.S. fall outside the U.S.M.C.A. trade agreement, according to one economist.

Former central banker Mark Carney will become Canada’s next prime minister after the governing Liberal Party elected him its leader as the country deals with U.S.

Carney, 59, a political novice, will take over at a tumultuous time in Canada, which is in the midst of a trade war with the United States.