Normally, no one would care that in a recent Atlantic essay -- "Why I hope to die at 75"-- 57-year-old Dr. Ezekiel Emanuel argued that living to be 75 years old was long enough for anyone. After 75, Emanuel suggests, "We are no longer remembered as vibrant and engaged but as feeble, ineffectual, even pathetic. But Emanuel is no garden-variety crackpot. Nor is he a wannabe science-fiction writer dreaming of a centrally planned planet of robust youthful humanoids. Unfortunately, he was one of the chief architects of the troubled Affordable Care Act and a key medical advisor to the Obama...