Robert Kaplan considers the Arabian Peninsula a shatter zone:
The vast tract of land controlled by the Saudi royal family is synonymous with Arabia in the way that India is synonymous with the subcontinent. But while India is heavily populated throughout, Saudi Arabia constitutes a geographically nebulous network of oases separated by massive waterless tracts. Highways and domestic air links are crucial to Saudi Arabia’s cohesion. Though India is built on an idea of democracy and religious pluralism, Saudi Arabia is built on loyalty to an extended family. But while India is virtually surrounded by troubling geography and dysfunctional states, Saudi Arabia’s borders disappear into harmless desert to the north and are shielded by sturdy, well-governed, self-contained sheikhdoms to the east and southeast.Where Saudi Arabia is truly vulnerable, and where the shatter zone of Arabia is most acute, is in highly populous Yemen to the south. Although it has only a quarter of Saudi Arabia’s land area, Yemen’s population is almost as large, so the all-important demographic core of the Arabian Peninsula is crammed into its mountainous southwest corner, where sweeping basalt plateaus, rearing up into sand-castle formations and volcanic plugs, embrace a network of oases densely inhabited since antiquity. Because the Turks and the British never really controlled Yemen, they did not leave behind the strong bureaucratic institutions that other former colonies inherited.
When I traveled the Saudi-Yemen border some years back, it was crowded with pickup trucks filled with armed young men, loyal to this sheikh or that, while the presence of the Yemeni government was negligible. Mud-brick battlements hid the encampments of these rebellious sheikhs, some with their own artillery. Estimates of the number of firearms in Yemen vary, but any Yemeni who wants a weapon can get one easily. Meanwhile, groundwater supplies will last no more than a generation or two.
I’ll never forget what a U.S. military expert told me in the capital, Sanaa: “Terrorism is an entrepreneurial activity, and in Yemen you’ve got over 20 million aggressive, commercial-minded, and well-armed people, all extremely hard-working compared with the Saudis next door. It’s the future, and it terrifies the hell out of the government in Riyadh.” The future of teeming, tribal Yemen will go a long way to determining the future of Saudi Arabia. And geography, not ideas, has everything to do with it.