text: Viggo Mortensen wore a shirt with this polity's flag on it to the premier of Return of the King.
full_question: Viggo Mortensen wore a shirt with this polity's flag on it to the premier of Return of the King. A "Vampire push" is used on Diana Jessup by the Transylvanian assistant attaché to this polity. The BBC once ran a segment that featured a logo from Halo instead of the logo of this entity's core members. This entity's government includes a body in which permanent members have veto power, called its Security Council. For 10 points, what intergovernmental organization's leaders have included Antonio Guterres, Kofi Annan, and Ban Ki-moon?
first_sentence: Viggo Mortensen wore a shirt with this polity's flag on it to the premier of Return of the King.