THAT THE FBI is investigating last week's San Bernardino massacre as an act of terrorism, after discovering that Tafsheen Malik, one of the shooters, had recently pledged allegiance to ISIS, has stunning implications.

This can not be considered typical of the kind of American mass murders for which we offer increasingly pallid thoughts and prayers to the victims while waiting around for the next one to happen. (And this year, we only had to wait one day for the next one, since 2015 has registered 350 mass killings.)

What distinguishes the latest horror is not just that a woman is involved, but the fact that we don't have to speculate about the motives or wonder how a troubled youth went off the rails. On this one, we may know why Malik and her husband mowed down 14 people: ISIS.

This latest example of the sophisticated global terrorism group reaching into American society is terrifying, because what a fertile ground it is, given our culture of unfettered access to and worship of guns. And not just guns, but guns of all kinds, including deadly assault weapons that can eliminate many lives in seconds. If ISIS continues to succeed in attracting Americans to its cause — so far, 250 citizens have been identified by Homeland Security as trying to engage with ISIS — it has a ready-made, already-equipped army here.

Gun supporters and their patrons at the NRA deny any connection to mass shooting and the unlimited number of firearms and assault weapons that flood the country, of course. To the followers of the NRA, guns are the solution, not the problem. In every case of mass shootings in this country, they offer excuses that have nothing to do with guns.

The San Bernardino killings will undoubtedly lead to calls for tighter restrictions on immigration and keeping the "wrong" people out.

In fact, the calls for more and more citizens to arm themselves has, sickeningly, already begun.

ISIS uses sophisticated communication techniques to attract its supporters. It builds on fear and offers a sense of belonging to increase its following.

The NRA also uses sophisticated communication techniques. It is now marketing itself as "Freedom's Safest Place," preying on fear and offering a sense of belonging to increase its following.

But we can't help thinking that the presence of ISIS that has emerged in the San Bernardino shooting can't be good for NRA's branding.

The NRA's mantra of the people's right to keep and bear arms which the Second Amendment promises for "a well regulated militia" may finally be confronting a fatal flaw: the realization that all these guns could also build an army of our enemies, right here on our soil.

Terrorism is happening around the globe, of course, and mass shootings do happen in countries that don't allow unfettered access to guns. On Saturday, three people were stabbed in a London tube station; the police are treating it as a terrorist incident. Here's the difference: All three people are still alive.

Yet again, we have an opportunity to apply commonplace regulations and controls on guns. President Obama last night called for tighter controls on assault weapons, and halting the ability of those on terrorist watch lists to buy guns. Our thoughts and prayers are for the United States to not become an armed camp, and for Congress to rescind its pledge of allegiance to the NRA and to the culture of killing that it promotes.