President Trump on Thursday retreated further from his threat to close the southern border, instead saying he would slap auto tariffs on Mexico within a year before closing the border in an attempt to stop drug trafficking and illegal immigration. “You know I will do it,” Trump told reporters in the Cabinet Room. “I don’t play games.” Trump described his newest threat as a “one-year warning” to the Mexican government to stem the flow of drugs and migrants traveling through its country en route to the U.S.