Yet, even if the optimists are right, America faces a host of ailments that seem beyond the reach of today’s politics. The personal tax code cannot be simplified without closing middle-class loopholes. Health care and pensions for an ageing population will swallow up the budget unless costs are curbed and the retirement age is raised. In each case, lasting reform will inflict pain on large groups of voters. Reforms are possible only if they have both parties’ fingerprints on them—if one side tried alone, the other would accuse it of throwing Grandma off a cliff. Cool heads in both parties know that the big entitlement programmes, which grow automatically, need fixing. Yet even in the most collaborative Congress, both sides would duck the issue, preferring instead to bicker over the mere 15% of the budget (excluding defence) that it re-authorises each year.