In a predawn raid on January 5, militants attacked a Saudi border post from the Iraqi side of the frontier.
The resulting clash left three soldiers and four militants dead.
It later emerged that one of the dead soldiers was no ordinary border guard but the commander of Saudi Arabia’s northern border forces, Brigadier General Awdah al-Balawi.
This suggests that the attack, far from being random or opportunistic, had been carefully targeted and perhaps based on inside information regarding the general’s whereabouts.
The attack has been widely attributed to the Islamic State, with some reports saying the rebel group has now claimed responsibility for it.
This might be viewed simply as a reprisal for Saudi participation in the U.S.-led bombing campaign against IS, but IS has also been seeking to extend the current conflict in Syria and Iraq into Saudi territory.
IS tends to flourish militarily in places where the central government is weak, but that is not the case in Saudi Arabia.
In military terms, the Saudi security apparatus is probably capable of suppressing IS on its own territory.
It is in no position to confront IS at the ideological level.
The problem here is that the IS and the Saudis’ Islamic kingdom are ideologically similar.
Hence attempts to challenge IS on ideological grounds risk undermining the Saudi state too.
The underlying issue is the rival claims of king and would-be caliph.
In the words of two Saudi government supporters: To restore the ‘caliphate’, [IS] would ultimately need to implant itself at the epicentre of Islamic life, the two holy mosques in Mecca and Medina.
Therefore, IS’s road to the caliphate runs through the kingdom of Saudi Arabia.
Inconveniently for the Saudi monarchy, this challenge from the upstart caliph comes at a time of uncertainty over the royal succession.
So far, Saudi efforts to confront IS ideologically have mainly taken the form of denunciations from tame clerics, but it is difficult to see what else they might do without calling their own state system into question.
The king and his princes have dug a hole for themselves by harnessing religion in the pursuit of power.
Religious credentials bolstered their claim to legitimacy and helped them assert their authority.
For a long time, those credentials served them well, but now they are becoming a liability and it may be too late to unfasten the harness.