A small nicotine pouch called Zyn has sparked a big debate among politicians, pundits and experts. The dispute reflects an increasingly complex marketplace in which companies like Philip Morris are promoting alternative products that may be less harmful than cigarettes and chewing tobacco. But health advocates fear Zyn, like electronic cigarettes, may catch on with teenagers due to its addictive nicotine. A recent warning about Zyn by a top Democratic senator prompted a swift backlash from Republicans and conservative pundits. Meanwhile, videos of young people popping the pouches have racked up millions of views on TikTok and other social media platforms.