WASHINGTON -- David Brooks of The New York Times wonders whether, as a lifelong Mets fan, he is morally permitted to jump ship and pledge allegiance to the new team of his (relatively) new hometown, the Washington Nationals (nee Montreal Expos). It's a charming dilemma, but it raises a more fundamental question: What is with this rooting business in the first place? It is one thing to root for your son's Little League team. After all, he is your kid, and you paid for his glove -- and uniform, helmet, bat, and, when he turns 9, cup. You have a...