Cambridge, Mass.

ON the second day of oral arguments over the Affordable Care Act, Solicitor General Donald B. Verrilli Jr., trying to explain what sets health care apart, told the Supreme Court, “This is a market in which you may be healthy one day and you may be a very unhealthy participant in that market the next day.” Justice Antonin Scalia subsequently expressed skepticism about forcing the young to buy insurance: “When they think they have a substantial risk of incurring high medical bills, they’ll buy insurance, like the rest of us.”

May the justices please meet my sister-in-law. On Feb. 8, she was a healthy 32-year-old, who was seven and a half months pregnant with her first baby. On Feb. 9, she was a quadriplegic, paralyzed from the chest down by a car accident that damaged her spine. Miraculously, the baby, born by emergency C-section, is healthy.

Were the Obama health care reforms already in place, my brother and sister-in-law’s situation — insurance-wise and financially — would be far less dire. My brother’s small employer — he is the manager of a metal-fabrication shop — does not offer health insurance, which was too expensive for them to buy on their own. Fortunately, my sister-in-law had enrolled in the Access for Infants and Mothers program, California’s insurance plan for middle-income pregnant women. AIM coverage extends 60 days postpartum and paid for her stay in intensive care and early rehabilitation.

But when the 60 days is up next week, the family will fall through the welfare medicine rabbit hole. As a scholar of social policy at M.I.T., I teach students how the system works. Now I am learning, in real time.