What underlies US inertia on mass shootings? It may be lack of trust.

As a commercial pilot certified to carry a gun while he flies, Paul Valone has had training on how to use a firearm to neutralize mass shooters and thwart terrorists.

It’s not with glee that the North Carolinian had to learn how to unjam a gun with one hand or manage it blindfolded. Rather he sees his skills acquisition as a civic duty, at a time when he says values are fraying in American life – underscored by the latest shooting to shock the nation: seven people shot dead at a...