FOR all the criticism of bailouts since the financial crisis struck, virtually no one has suggested that depositors in banks be made to suffer along with their investors, employees and customers. Until this week, when the euro zone proposed that, in return for a bailout of the failing banking system in Cyprus, depositors pay a “tax” of 6.75 percent of their deposits — 9.9 percent for deposits above 100,000 euros. Because bank deposits in Cyprus, and virtually everywhere, are insured, the plan shocked many people who figured that this insurance was the one financial safety net that was still truly...