Remember that classic Beatles riff of the 1960s: “You say you want a revolution?” Imagine this instead: a devolution. Picture an America that is run not, as now, by a top-heavy Washington autocracy but, in freewheeling style, by an assemblage of largely autonomous regional republics reflecting the eclectic economic and cultural character of the society.

There might be an austere Republic of New England, with a natural strength in higher education and technology; a Caribbean-flavored city-state Republic of Greater Miami, with...