Americans don't yet know exactly what triggered a mentally ill young man in Newtown, Conn., to use his mother's weapons first to execute her, and then to go to Sandy Hook Elementary School and massacre 20 children and six teachers.
His actions were the latest in a series of affronts to all that is right and decent, and justly fueled calls for actions to prevent similar outrages.
Here's to thoughtful, measured action that improves public safety while preserving the freedoms to which Americans are entitled under the 2nd Amendment to the Constitution.
As many commentators have noted, simply neutering the right to bear arms would not prevent mass shootings. It would affect only the law-biding.
Although most people with mental illnesses pose no threat of violence, it's clear that mental illness is as much an ingredient in mass shootings as firearms are.
President Obama tacitly acknowledged this when he announced executive actions and proposals to address the problem.
To his credit, the president's proposals include both measures aimed at gun owners and gun buyers and
actions aimed at better identification and treatment of mental illness in young people - the demographic that has been involved in many of the worst atrocities.
"Disorders of the mind and perhaps of brain chemistry usually manifest in adolescence or early adulthood, and the focus of a reformed system should be identifying them as sickness emerges," the Wall Street Journal said.
For example, the president suggests spending $75 million on programs to identify high-risk young people and train more health professionals to help them.