Like two sides of a coin imprinted with the nation’s motto, “e pluribus unum” — out of many, one — America’s political factions are cast in opposition, but they are intrinsically bound together as parts of a larger whole. From the beginning, the United States has aspired to build a more perfect union. When our founders convened the Constitutional Convention in 1787, they disagreed about the structure of government, the balance of power and the p…