A legal battle over the reach of religious freedom returns to the Supreme Court on Wednesday, requiring the justices to consider whether the Constitution allows a religious freedom exception to anti-discrimination laws. The dispute, between the city of Philadelphia and a Catholic charity that refuses to place children in foster care with same sex-couples, is the first of this term’s blockbuster cases to be heard with Justice Amy Coney Barrett on the court. The decision is likely to have a nationwide impact. Since the Supreme Court struck down laws against gay marriage in 2015, lawsuits have sprung up around the nation brought by bakers, florists, photographers and others who say their religious beliefs will not allow them to provide services for same-sex weddings.