US law insists on the separation of church and state. So why does religion now govern? Montgomery, Alabama, is no stranger to stand-offs. The gold star embedded into the marble at the front of the state capitol marks the spot where Jefferson Davis stamped his foot and declared an independent Confederacy and where former governor George Wallace promised "segregation now, segregation tomorrow, segregation forever". From that very point you can make out the bus stop where Rosa Parks took her seat and the church where Martin Luther King made his stand, launching the bus boycott that sparked a decade of...