The gun industry launched the project approximately 17 months before the 2000 election as it grappled with a cascade of financial, legal and political threats. Within three years, the NSSF’s database — filled with warranty card information and supplemented with names from voter rolls and hunting licenses — contained at least 5.5 million people.

Jon Leibowitz, who was appointed to the Federal Trade Commission by President George W. Bush in 2004 and served as chair under President Barack Obama, reviewed several company privacy policies and warranty cards at ProPublica’s request. The commission has enforced privacy protections since the 1970s.

Leibowitz said firearms companies that handed over customer information may have breached federal and state prohibitions against unfair and deceptive business behavior and could face civil sanctions.