Rick Santorum’s Catholic faith is an obvious centerpiece of his campaign for the GOP presidential nomination, and it is rare for him to speak without referencing his religious beliefs. It is also rare, however, to hear him speak about his particular church, St. Catherine of Siena, which he and his family have belonged to for at least a decade. Even his 2005 manifesto on his personal faith and politics, It Takes a Family, did not mention the church. I was curious to learn more about it, so last Friday morning, I attended a 9 a.m. Mass there. St. Catherine is...