President Obama was right last week to focus his thoughts—and ours—on the victims of the Tucson rampage and the lives they led. Those who gathered that day were doing something fundamentally American: they were meeting with their elected representative at a “Congress on Your Corner” event, participating in the give-and-take of the democratic process. For nearly 200 years, Americans have also been rightly haunted by that strange subspecies of citizen that is their opposite: those who see killing political leaders as a better form of self-expression. They are a sorry lot, mostly a collection of sexually frustrated loners and misfits united only by their common background in social isolation. But they, too, are a longstanding part of the American fabric.

They may have something to teach the rest of us, however unintentionally, about the consequences of our atomized country. Where political violence in other countries is nearly always associated with extremist movements, religious fundamentalism, or criminal organizations, American assassins are usually peculiar stalkers defined less by ideology than vague political and personal grievances…

“These types of assassins, these American boys, are really reflective of the youthfulness of our culture,” says Paul Schrader, the screenwriter of Taxi Driver, which was influenced by the story of Arthur Bremer, who paralyzed Governor Wallace for life. “America is a relatively young country, and particularly young men still think that, as Americans, the world should be theirs. And if it isn’t, there’s somebody else to blame.”