THE BURNED OVER DISTRICT

Saudi Arabia, which has terrorized the Muslim world for years with its cruelly anti-humanist stain of Wahabist Islam backed by unlimited oil money, is now seeing that fundamental, and fundamentally flawed, religious extremism turned back upon itself.

The video spread rapidly across the kingdom, shocking a nation struggling to contain a terrorist movement seen as especially dangerous not just because it promotes violence, but also because it has adopted elements of Saudi Arabia’s intolerant version of Islam — a Sunni creed known as Wahhabism — and used them to delegitimize the monarchy.

“Wahhabism is fundamental to the Islamic State’s ideology,” said Cole Bunzel, a scholar of Wahhabi history at Princeton University and the author of a recent paper on Saudi Arabia and the Islamic State. “It informs the character of their religion and is the most on-display feature, in my opinion, of their entire ideology.”

Among 20 terrorist episodes in Saudi Arabia since late 2014, the killing of Sergeant Rashidi was the third in which citizens had secretly joined the Islamic State and killed relatives in the security services. In each case, they justified their acts by saying Saudi Arabia practiced a corrupted version of the faith, a charge aimed at a kingdom that holds itself up as the only true Islamic state.

The Islamic State, like Al Qaeda before it, accuses the Saudi monarchy of corrupting the faith in order to preserve its power. But Qaeda networks in the kingdom were dismantled years ago, and the group’s leadership abroad has discouraged killing Muslim civilians.

The Islamic State, however, has been able to infiltrate the kingdom through digital recruiting, and it has found devotees willing to kill fellow Sunnis, as well as Shiites, to destabilize the monarchy.

Now the Islamic State poses a new challenge, by turning aspects of Saudi Arabia’s fundamentalist creed against it. Wahhabism has been molded over the years to serve the interests of the monarchy, emphasizing obedience to the rulers and condemning terrorist attacks, even against those seen as apostates.

Still, among the Islamic State’s many enemies, Saudi Arabia is the only one that considers the Quran and other religious texts its constitution, criminalizes apostasy and bans all forms of unsanctioned public religion.

Wahabism grew because it justified the lust for power of the tribe of Saud. And now it is being turned against the Sauds by another group with a lust for power. And all of it is wrapped up in the cheap paper of religion.