Emboldened by success, and imbued with a fanatical and paranoid world-view, they see enemies everywhere and regard any hint of compromise as betrayal. As New York Tribune editor Horace Greeley wrote in 1854, slavery "loves aggression, for when it ceases to be aggressive it stagnates and decays. It is the leper of modern civilization, but a leper whom no cry of 'unclean' will keep from intrusion into uninfected company." Much the same applies to the NRA and its insatiable appetite for new territory to allow arms in, and new ways to allow those guns to be used--such as putting armed guards in our elementary schools, as the NRA today suggested.
The policy goals are different now, obviously. But the way in which the GOP and NRA think about the world is similar. Someone is always ready to take all their guns away. The same is true of all important forms of liberty they value; taxes and unchecked capitalism being two main ones.
I think the kind of paranoia Horwitz describes is central to the modern GOP. I say it's central to the GOP because I don't think it's central to all conservatives. Many people are conservatives because of a skepticism towards centralized power. Many liberals, including myself, share that skepticism. We just disagree sometimes on where to place that skepticism (conservatives more towards the federal gov't, liberals more towards private enterprise) and what the solutions should look like. But the group of conservatives that have a paranoid worldview have taken over the GOP. And it's no coincidence that they did so following the passage of the Civil Rights Act.
In short, the NRA has become a neo-Confederate movement that sees Federals as foes, and that stokes the paranoia of its followers by claiming, as LaPierre did this year, that Obama's re-election marks "the end of our freedom forever." That's more or less what Fire-Eaters said about Lincoln in 1860.
The parallel that is most interesting to me is that the constant in both situations is white male privilege. They didn't want to give up slaves because the slaves were their property, literally a source of their wealth. The modern GOP doesn't want to give up guns or more taxes because the guns protect their wealth and the taxes take that wealth and give it to people who aren't privileged white men. The roots of the paranoia are self interest. Sadly, it seems that the recent events in Newton aren't even enough for some (or at least someone like the NRA leader LaPierre) to put that aside for the greater good.