It may well be that Wayne LaPierre and his fellow White Geezer Gunners at the helm of the National Rifle Association are just plain wacked: shrieking zealots who have lost touch with their own organizational interests as well as the basics of human morality.
But I think it is just as likely that the NRA's top brain trust is crazy like a fox. I see one demonstrated reason for this, and also an unproven but evilly feasible reason.
The demonstrated reason comes from the chief axiom of America's increasingly frightened White Far Right: the best strategy for a right-wing white fringe that finds itself losing both the demographics and the public debates is to become so audacious, so bloodthirstily provocative and wildly uncompromising, as to scare money-whipped politicians and terrified white voters alike into whimpering agreement with NRA ideas that are way out of whack with voters' deeper desires and interests. This has been the tactic, for instance, of the Republican Party since 2008, and while it may appear suicidal in the long run, it is actually the sensible option for a cadre that has nothing to lose. With the NRA, as with the GOP, if they hard-line it the worst that can happen to them is the kind of defeat that would happen anyway if they were to yield now to demographics and the public's better instincts. And their best-case scenario is that they secure wins for their agenda that protect their power in spite of the fact that their arguments make no actual sense. So the NRA, ruthless power broker that it is, is going for it.
And then there is the not-yet-proven but evilly feasible reason: Even if the NRA, like the Repubs, sacrifices itself on the altar of broader public opinion, it wins a victory in consolidating the fear and fury of a sector of the white electorate that will accept increased state violence against designated "others" (blacks, Latinos, Muslims, the poor) in exchange for whites' perceived "freedom" to protect their own personal stature with guns. And it so happens that this political transaction serves and pleases those who most aggressively underwrite the Republican Party and the NRA: the very meanest of the rich.
Seen this way, the NRA's ignoring broader public wishes in order to whip up the loyal fury of its relatively narrow base is one of the few practical – and profitable – gambits it has left.

