A fifth of Americans call themselves Catholic. The Roman Catholic Church is in every meaningful way mainline, with its stable hierarchy that shapes and enforces doctrine and practice. In this sense, America has been a four-hundred-year-long natural experiment testing how religion develops with and without a powerful central organization. In other words, a big reason American Catholics are more reality-based than Protestants is because tenured grown-ups, from the Vatican on down, have consistently been in command, tamping down and pinching off undesirable offshoots.
