This morning, a car bomb exploded outside a mosque in Saudi Arabia, the second such attack in a week. The attacks, which have killed at least 25 people, were aimed at the minority Saudi Shi’a community. In doing so, ISIS is expertly capitalizing on Saudi Arabia’s internal sectarian divide, which is worsened not only by domestic repression, but by the propaganda supporting Saudi Arabia’s activist foreign policy in Syria, Yemen and elsewhere. Saudi rulers should remember that sectarianism, though convenient for political purposes, also carries substantial risk.

In an interview shortly before the recent Camp David summit, President Obama committed the faux-pas of pointing out the internal problems faced by many of the GCC states. He noted that these states contain “populations that, in some cases, are alienated, youth that are underemployed, an ideology that is destructive and nihilistic, and in some cases, just a belief that there are no legitimate political outlets for grievances… The biggest threats that they face may not be coming from Iran invading. It’s going to be from dissatisfaction inside their own countries.”

He’s not wrong. Saudi Arabia is well-known as one of the world’s most repressive states, with little political representation and no rights for women or minorities. Further, oil prices remain low, and while the Saudi state has massive cash reserves, the rise of shale oil has diminished its role as the world’s main oil producer. Saudi Arabia also has a growing youth population, with 51% of the population under the age of twenty five.

This is itself less concerning than the inability of the oil-dependent Saudi state to provide stable employment opportunities; the unemployment rate for those between fifteen and twenty-five years of age is at least 30%. It is no wonder that many of the unemployed youth of Saudi Arabia are attracted by movements like ISIS. Indeed, by some estimates, more than 2,500 of the foreign fighters in Syria come from Saudi Arabia. The newest iteration of this threat is seen in attacks like those of the last week, as young men susceptible to ISIS avoid travel to Syria, and instead carry out attacks inside Saudi borders.

Yet the ISIS attacks also highlight the pernicious influence of state-supported sectarianism. The bombers astutely aimed the bombings not at Sunnis, but at the state’s minority Shi’a population. While targeting Sunnis would likely have increased resolve among Saudi citizens, targeting Shi’a mosques instead served to cast worshippers as heretics, highlighting domestic sectarian tensions.

The attacks remind Saudi Shi’ites that their own government uses sectarian messaging on state TV, and has close ties to clerics which rail against Shi’a heretics. Shi’ites in Saudi Arabia don’t even enjoy the same minimal political rights that their Sunni compatriots do, and the state has repeatedly cracked down on calls for increased representation.

These tensions are being further inflamed by the war in Yemen, which is being presented by Saudi state TV as a crusade against Houthi Shi’ites. The same applies to the state’s newly activist foreign policy, which is portrayed broadly as a challenge to Iranian and Shi’a interests across the region. The high civilian death toll in Yemen – as many as 2,000 people – and the reticence of the Saudi government to seek a political settlement with the Houthis also contributes.

In short, the ISIS attacks targeted a potential cause of instability within the Saudi state, requiring Saudi rulers to strike a delicate balancing act. They must show support for the attacked communities, while avoiding upsetting the hardline Sunni clerics which support the royal family. Balancing these factors while continuing to use sectarian language to justify the state’s wars in Yemen and elsewhere may prove impossible.

As the Arab Spring illustrated, even states which appear relatively stable can suffer from instability and chaos. It also showed that once the Pandora’s Box of sectarianism has been opened, it is extremely difficult to shut. As ISIS attacks within Saudi Arabia seek to increase tensions between Sunni and Shi’a populations, this is a lesson Saudi Arabia’s rulers would be wise to bear in mind.