Bangladesh, Aug. 21 -- or much of the 20th century, the United States represented not just a place on the map. It was also a point in time. When Western Europeans looked at images of America after World War II-depictions of Hollywood's glamour, American cars, and newfangled labour-saving devices-they thought they were looking into the future.

The American Dream had an especially irresistible draw for East Europeans behind the Iron Curtain, and for tens of millions of Chinese during the opening and reform era that began after Mao Zedong's death in 1976. China's great economic reinvention was inspired, in part, by Deng Xiaoping's awe at American modernity, which he witnessed firsthand during an official visit in 1979.

But fast-forward to...