Still, several of this year's mass murders could have still occurred, even if all three of these measures had been in place. Pennington said this fact underscores the need to talk about gun sales to mentally disturbed individuals.
"We could have an open-ended discussion in this country about the Jiverly Wongs of this world," he said. "The mental health aspect is not a part of our core agenda right now, but it could be if we all, as a country, had a conversation about it."
Associated Press reports contributed to this story.