Diving into the rich pool

ASKED why he robbed banks, Willie Sutton, a hold-up artist of some accomplishment during America's Depression, answered simply: “Because that's where the money is.” Advanced economies that have piled up debts are eyeing their rich for similar reasons. The way to begin filling holes in the budget, many suggest, is by extracting more from those who have done best. This week Barack Obama proposed paying for new stimulus measures and deficit cuts by reforming the tax system to ensure that millionaires do not pay a lower tax rate than middle-class families.