“The brutal arithmetic is that total federal health spending is about 10% of GDP today and on pace to hit 15% in 20 years. The liberal response is more central planning and eventually the political rationing of care, even as taxes continue to climb. The alternative that Mr. Ryan has offered, including an ObamaCare repeal and a conversion of Medicaid into block grants to states, would bring that share down to 6% as premium support began to limit Medicare’s open-ended spending.”