In a dramatic, last-minute move, the Trump administration agreed Monday to pause sweeping tariffs on Mexico for a month while the two sides hammer out an agreement on security and trade, the U.S. and Mexican leaders announced.

As soon as the sun glints over miles of border fence dividing the United States and Mexico, the engines of cargo trucks packed with auto and computer parts roar to life along border bridges and bleary-eyed workers file into factories to assemble a multitude of products geared toward the U.