What is the real (inflation-adjusted) interest rate that the US or Western European core economies will have to pay on that extra $50 billion of debt? If it is 1%, boosting demand and production by $150 billion next year means that $500 million must be raised each year in the future to keep the debt from growing in real terms.
美国或西欧核心经济体需要为这笔500亿美元的新增债务付出怎样的真实（经通胀调整的）利率？如果利率为1%，那么在明年提振1 500亿美元的需求和生产意味着在未来需要每年拿出5亿美元来保证这笔债务的真实价值不会增加。如果利率为3%，那么年税收额必须增加15亿美元。如果利率为5%，政府每年需要拿出25亿美元的额外开支。