In January 2019, Baldwin was one of 40 senators to introduce the Background Check Expansion Act, a bill that would require background checks for either the sale or transfer of all firearms, including unlicensed sellers. Exceptions to the bill's background check requirement included transfers between members of law enforcement, loaning firearms for either hunting or sporting events on a temporary basis, giving firearms to members of one's immediate family, firearms being transferred as part of an inheritance, or giving a firearm to another person temporarily for immediate self-defense.