The U.S. House of Representatives recently passed a bill that expands background checks for gun sales. Currently, background checks are only federally mandated when a firearm is purchased from a person or business that holds a federal firearm license (FFL). No such requirement is imposed on unlicensed sellers.

Under federal law, people must obtain an FFL if they sell firearms as part of “a regular course of trade or business with the principal objective of livelihood and profit.” Individuals who make “occasional sales,” on the other hand, do not need to obtain an FFL. This law was written more than 25 years ago, at a time when Congress could not have envisioned the vast and unregulated online market for guns that exists today.