CHESTER, Va. — The Christian preschool teacher heard the news on her car radio: Same-sex marriage is now legal in Virginia. This is it, she thought. The end times. “It could happen today,” Pam Rives said on Tuesday, tidying her lemon-yellow classroom at the Ironbridge Baptist Church. “This is just another step in that direction. As society changes, it takes God out of it.” Rives, 57, has taught 4-year-olds for nearly a decade in this conservative pocket of the South, which is home to 20,000 residents. Her school, lined with October pumpkins and bubble-lettered prayers, is down the road from...