Deirdre Reilly: What's to blame for our killer youth?

When I sent my middle son to college, I had the normal worries associated with a loved child's departure from home - would he eat enough? Rest enough? Study enough? One thing I never asked myself, though - is he fast enough if he had to outrun a gunman? This, sadly, is what American parents now are facing when it comes to their college students attending schools all over the country.