He was limp and dusty from an explosion, conscious but barely. A far cry from the fierce, masked Islamic State fighters who once seized vast swaths of Iraq and Syria, the captive was a scraggly teenager in a tank top with limbs so thin that his watch slid easily off his wrist.

For decades, there was an unvaried rhythm to life in America's suburbs: Carpool in the morning, watch sports on weekends, barbecue in the summer, vote Republican in November. Then came President Trump.