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For over a decade, conventional wisdom has held that the future of the world economy rests on the rise of the so-called BRIC countries: Brazil, Russia, India, China (and, in some cases, with the addition of an ‘S’ for South Africa). A concept coined by Goldman Sachs economist Jim O’Neill, the BRICs were widely touted as the building blocks of the “post-American world.”

Such notions are particularly popular among intellectuals like India’s Brankaj Mishra, who sees world power shifting inexorably to “ascendant nations and peoples” — i.e. the BRICs — while “America’s retrenchment is inevitable.” Yet in reality, it is increasingly clear that the BRICs upward trajectory is slowing and many long-term trends suggest that their growth rates will continue to...