John Whitehead in Port St. Joe, Florida, this month. (Erich Martin/For The Washington Post) In the beforetimes, when Americans weren’t yet debating whether Starbucks holiday cups were Christmas-y enough or whether bakers should make cakes for same-sex weddings, a lanky Southerner named John Whitehead started something totally new: a Christian religious liberty law firm.It was hard to raise money, Whitehead recalled, or get support for the firm - even from evangelical leaders - for Christians fighting in court for the right to home-school or a police officer wanting to wear a cross to work.“They said ‘Christians don’t sue,’ or that...