chris pollone, nbc news, back to you. >> many thanks to chris. now to try to talk something sensible about this, we welcome blake zeft to the show, a former obama presidential campaign aide. we welcome back nan hayworth and mark simone. nan, let me begin with you, please. you're a doctor. >> yes. >> i know you're not a mental health doctor. but it has been alleged that he has asperger's syndrome, personality disorders -- nobody knows. does mental health play a huge role in this, from what you know? >> well, i'm the mother of two sons as well. i just can't imagine the scene at that elementary school. and of course the families whose children survived. these children who witnessed this. there's no explanation for these things, clearly, larry. and this is the latest in a series of shootings this year. every one of them has been perpetrated by someone who has been deemed to be exceedingly mentally ill. we do have a problem as a society in identifying those who need help so that they won't do these things. and it's a very, very difficult problem. it's