Reading the new history of the IRA, I thought of a passage from Calvin Trillin's "Killings." In "Killings," two neighbors become involved in an endless feud. It's a feud about a very tiny piece of land. The feud ends with one neighbor shooting and murdering the other neighbor. As someone else in the town said, "Both parties were wrong. Everything could have ended if someone had said, I was wrong and I'm sorry ." The byzantine struggles between the Irish and the English are so complex and so tricky to follow. The English were brutal. Relentlessly brutal. The IRA responded by becoming brutal. Relentlessly brutal. The stink of evil is on both parties. An iconic photo from the era of the Troubles seems to suggest how awful and how infectious the evil was: A priest kneels by the corpse of a murdered Irishman, and the man's blood is now on the priest's lips, like a ghoulish kind of lipstick, because the priest has attempted (and failed a...