The line comes about 1:30 into the video above. The line references this answer by VP Biden in an interview from earlier this year which was proven false. I love where the Huffington Post below claims David Frum is a Conservative. My Liberal brother is way more Conservative than David Frum.
Sadly, none of the panelists talked about the real problem and that is reforming the background check system and doing more for mental illness in this country. No amount of gun control can prevent mass shootings.