Air Base 201 in Niger was the U.S. Air Force's largest construction project in history: a massive drone center that cost American taxpayers $280 million. Thanks to a change in the Nigerien leadership, Americans may have to give up that investment for good. Niger's new nationalist government, which took power in a coup d'etat last year, has been trying to get rid of foreign military presence in the country. Over the weekend, Nigerien Col. Amadou Abdramane ordered U.S. troops out of Air Base 201, declaring on television that "the American presence in the territory of the Republic of Niger is...