A week back in the United States, former ambassador to China Jon Huntsman Jr. on Sunday didn’t head to one of the six Mormon churches in the Charleston, S.C., area where he was visiting potential supporters and donors while deciding whether to launch a presidential bid. Instead, Huntsman headed to a nondenominational mega-church called Seacoast with a rising star congressman, Rep. Tim Scott, who could be a key supporter in this early primary state.