(Meg Kinnard | AP file photo) Democratic presidential candidate and former vice president Joe Biden attends a Sunday service at Morris Brown AME Church in Charleston, S.C., July 7, 2019. A Catholic priest in South Carolina denied communion to Joe Biden over the weekend, a decision purportedly made over the former vice president’s stance on abortion. It illustrates the tricky challenge facing presidential candidates as they share their faith on the trail: How to balance the private and deeply personal values of their religions with a public campaign schedule that pushes them to authentically choose a side in polarizing moral debates?