McCarthy was one of the nation's most vocal gun control advocates. In 1997, she sponsored a bill requiring trigger locks on guns. After the 1997 Empire State Building shooting, she introduced legislation to ban the sale of guns to tourists visiting the United States; afterwards, she received "threats serious enough to require police protection during most public appearances". Later that year, McCarthy unsuccessfully opposed a Treasury bill provision that allowed the importation of weapons that had been modified in order to be compliant with the federal assault weapons ban. In the aftermath of the Columbine High School massacre, McCarthy proposed a bill that would require firearms to be child-resistant, would make it more difficult for young adults to purchase guns, and would regulate gun shows.