American football is more than a sport. For millions of people across the United States, it is a weekend ritual, a family tradition, a social gathering, a source of civic pride, and an enduring part of popular culture. From youth leagues and high-school stadiums to the spectacle of the Super Bowl, football occupies a peculiar and powerful place in American life. It is loud. Dramatic. Tactical. Occasionally bewildering. And remarkably resilient. The National Football League (NFL) has transformed professional football into a vast entertainment industry, while college football has cultivated generations of intensely loyal supporters. High-school football, meanwhile, remains deeply embedded in many local communities. But what explains this extraordinary…