EXCLUSIVE: Jewish student leaders from across the United States gathered Monday in the nation’s capital for the Israel on Campus Coalition’s National Leadership Summit, where they heard an address from the parents of an American-Israeli hostage killed by Hamas. Jon and Rachel Polin, the parents of 23-year-old Hersh Goldberg-Polin, delivered a direct appeal to the group of more than 700 students: find your purpose, speak with courage and help secure the release of the 50 hostages still believed to be held in Gaza. "Pull your shoulders back, head up, be proud, engage, try to truly learn and listen," Jon Polin...