Although people with serious mental illness have committed a large percentage of high-profile crimes, the mentally ill represent a very small percentage of the perpetrators of violent crime overall. Researchers estimate that if mental illness could be eliminated as a factor in violent crime, the overall rate would be reduced by only 4 percent. That means 96 percent of violent crimes — defined by the FBI as murders, robberies, rapes, and aggravated assaults — are committed by people without any mental-health problems at all. Solutions that focus on reducing crimes by the mentally ill will make only a small dent in the nation’s rate of gun-related murders, ranging from mass killings to shootings that claim a single victim.

Margo Sanger-Katz, National Journal

So regarding the safety of our country, that whole "let’s focus on mental health instead of stronger gun laws" argument goes right out the window.