Sarita Latchman, a vibrant 42-year-old mother and former parks worker, has a sound like a baby’s rattle at the back of her throat. Which is not surprising, as her apartment in the Jefferson Houses in East Harlem is speckled with soot-black mold. A thick carpet of it runs down her bathroom wall and across the ceiling of her children’s bedrooms. Rub it and the spores float, landing on sink tops and children’s hair. They also journey through Ms. Latchman’s nasal passageway into her lungs.

In 2006, then-Massachusetts Gov. Mitt Romney helped save the lives of two sick women: Tammy Stafford and Lavern Barnes. If we lived in the era of silent films, Stafford and Barnes would be tied to train tracks and resigned to their fates. Then the governor and his deputies would ride in, vanquish the varmints who put the ladies there and release them just before the train roared through.