After the Columbine High School massacre on April 20 , 1999 , gun shows and background checks became a focus of national debate in the United States . Weeks after the Columbine shooting , Frank Lautenberg introduced a proposal to close the gun show loophole in federal law . It was passed in the Senate , but did not pass in the House
Columbine High School massacre
Columbine High School massacre
Gun show loophole