Health-care services account for some 17 percent of the country’s gross domestic product; today, the average family pays an additional $1,000 annually in the form of higher premiums to subsidize the costs incurred by those who receive care but do not carry insurance. The mandate is an indispensable tool for achieving the government’s compelling goals of universal coverage and lower costs. Insurance companies would be unable to offer affordable coverage to those with preexisting conditions, for example, unless they also were guaranteed enrollment of the young and healthy customers who are less likely to consume health-care services.