Take health care.He cannot substantially and permanently expand coverage (a Democratic priority) unless he also tackles soaring health-care costs (a Republican one).Or take climate change.

• 就拿卫生保健而言，他不可能大幅永久的扩大支出（民主党首选），除非他同时可以解决飙升的卫生保健成本（共和党观点）。