Whose primary responsibility is it to regulate the importation of arms?

The correct answer is the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) because this agency is specifically tasked with regulating the importation, manufacturing, and distribution of firearms and ammunition in the United States. The ATF enforces laws related to the control of weapons and explosives, ensuring compliance with regulatory requirements, including those pertaining to the importation of arms. Their responsibilities also encompass the investigation and prevention of illegal trafficking of firearms, making them the primary authority in this area.

In contrast, other agencies such as HSI, FBI, and DEA have different mandates: HSI focuses on immigration and customs enforcement along with investigating transnational crime, the FBI handles domestic intelligence and criminal investigations, and the DEA is primarily focused on combating drug trafficking and distribution. Therefore, while all these agencies play critical roles in law enforcement, only the ATF is dedicated to the regulation of arms importation.