Terrorists Shouldn't Have Guns

Omar Mateen, who killed 49 people in an Orlando nightclub Sunday, was a walking red flag. He was abusive, unstable and prone to rages. He boasted of ties to every terrorist group under the sun. He expressed a vast catalog of hatreds and resentments. According to a former colleague, he "talked about killing people all the time."

These warning signs didn't go unnoticed. The FBI added Mateen to its main terrorist watch list, placed him under surveillance, prodded him with an informant, recorded his conversations and interrogated him more than once.