Almost five years ago Thomas Schaller published an important book titled Whistling Past Dixie, which basically argued that it was time for Democrats to stop running scared of the views of Southern whites — they weren’t going to get those votes anyway, and demographic change had proceeded to the point where they could win national elections without the South. Indeed, so it has come to pass: while Obama did win Virginia, he did it by appealing to the new Virginia of the DC suburbs, not the rural whites, and otherwise he had a totally non-Dixie victory.

So Nate Cohn argues that this same logic applies to gun control: the voters who care passionately about their semi-automatic weapons are rural whites who ain’t gonna vote Democratic in any case — and the new Democratic coalition doesn’t need them. David Atkins takes it further, saying the awful truth: the pro-gun fanatics are basically the kind of people who think that Obama is a Kenyan socialist atheistic Islamist, and the urban hordes are coming for their property any day now. People, in other words, who already vote 100 percent Republican — and lose elections.

As Cohn says, it’s not clear whether Democrats realize how things have changed. But maybe yesterday’s horror will provoke some fresh thought, and they’ll realize that this does not have to go on.