• To scholars of the Great Wall, the figurative use of Chinese wall is one of those ironies that only history, with its perverse sense of humor, could produce. As it happens, the Great Wall was pretty lousy at keeping out foreigners, in particular Mongols, who repeatedly crossed over the wall during the Ming Dynasty, said Arthur Waldron, author of “The Great Wall of China: From History to Myth.” “Mongols breached the wall in some cases because those guarding the gates opened them,” he said in an interview, “or because portions of the frontier were inevitably poorly guarded and in decay, or by bribery.”

    Bribery? The Great Wall, it turns out, is a perfect emblem of the Chinese walls now under scrutiny, though not for the reason that anyone thinks. The original, like its criticized namesakes, didn’t work very well — and turned downright porous when money was involved.