Whether looming over public squares or dotting old battlefields, monuments certify a culture's present by securing its past and pledging its future. They embody exemplary persons or events and the shared ideals they stood for, prompting an obligation to keep those ideals standing now and forever. But monuments also exaggerate the staying power of civilizations and of art. In the second half of the twentieth century, postmodern critics often decried monuments not only for their pretensions and stiffness but also for their supposed role in perpetuating oppressive cultural conventions. Even so,...