Three American presidents have spent nearly 16 years alternately cajoling, coaxing, threatening and bombing Pakistan, all with a goal of trying to change the Pakistani government’s decisions about the factions it supports in Afghanistan’s desperate civil war. The latest of those, President Trump, tried a different approach during his speech on Monday night. After chastising Pakistan for harboring militants and terrorists, he called on India — Pakistan’s archrival — to flex its economic influence in Afghanistan to help stabilize the country.