In America's health-care dialogue, emergency rooms have come to symbolize the system's economic and medical defects. To critics, typical ERs are swamped by the uninsured, who — lacking a regular doctor or source of care — go where they will be treated. Performing routine medicine at high prices, ERs are crowded and costly. If the uninsured had insurance, these problems would recede. Better medicine at less cost. Who could oppose that? Well, nobody. It was a selling point for the Affordable Care Act. The trouble is that the story is mostly make-believe.