NATO marked the 75th anniversary of its founding with a ceremony in Brussels on Thursday amid a heightened Russian threat and lingering questions over the alliance’s future. After laying a wreath in memory of military personnel of NATO countries killed in service, the alliance’s Secretary General Jens Stoltenberg said the United States and Europe need one another for their own security. “Europe needs America for its security,” Stoltenberg said. “At the same time, North America also needs Europe. European allies provide world-class militaries, vast intelligence networks, and unique diplomatic l…