This article appears on the very day when Congress passed yet another bill to end The Affordable Care Act. The number of uninsured Americans has fallen by an estimated 15 million since 2013, thanks largely to this act, but a new survey, the first detailed study of Americans struggling with medical bills, shows that insurance often fails as a safety net. Health plans often require hundreds or thousands of dollars in out-of-pocket payments — sums that can create a cascade of financial troubles for the many households living paycheck to paycheck.