Half a century after the 18th-century political philosophers Mary Wollstonecraft and William Godwin pioneered the marriage of equals, and just as Ralph Waldo Emerson and Margaret Fuller were contorting themselves around the parameters of true partnership, another historic power couple modeled for the world the pinnacle of an intimate union that is also an intellectual, creative, and moral partnership nourishing not only to the couple themselves but profoundly influential to their culture, their era, and the moral and political development…