American musical royalty steps out as American political royalty in a glittering company premiere. Thomas Hampson appears as the later disgraced 37th President at one of his finest hours. Renée Fleming is Pat, who, receiving a gift of a little glass elephant, wants to know if it’s one of a kind. (“It has been carefully designed by workers at this factory,” she is told. “They can make hundreds every day.”) Gustavo Dudamel conducts the first and arguably still the best of the now nine John Adams operas. The production is by Valentina Carrasco, of Argentina, who, we are told, emphasizes “the importance and mediating power of Chinese national sport in history.” Remember ping-pong diplomacy? —Matthew Gurewitsch