Oregon Governor Kate Brown signed a bill Monday that will require criminal background checks for anyone who buys a gun from a private party.
Background checks are already required for guns purchased through licensed dealers or at gun shows. Brown said the new law closes a loophole.
"We have an obligation to protect Oregonians from gun violence,” the governor said. “If we want to keep our kids, schools and communities safe, we must make it harder for dangerous people to get guns."
The measure passed with no Republican votes. Critics call the law intrusive and say it will do little to prevent determined criminals from getting their hands on weapons.
Opponents say they're planning a rally at the state capitol this month to publicly state that they won't follow the background check requirement when purchasing guns.