Robert D. Kaplan writes mostly about politics and conflict. But there is much of importance to economists. Some excerpts follow.

there is a certain geographic logic to where certain ideas take hold. Communist Eastern Europe, Mongolia, China, and North Korea were all contiguous to the great land power of the Soviet Union. Classic fascism was a predominantly European affair. And liberalism nurtured its deepest roots in the United States and Great Britain, essentially island nations and sea powers both. Such determinism is easy to hate but hard to dismiss.

…In three decades covering the Middle East, I have watched it evolve from a largely rural society to a realm of teeming megacities. In the next 20 years, the Arab world’s population will nearly double while supplies of groundwater will diminish.

A Eurasia of vast urban areas, overlapping missile ranges, and sensational media will be one of constantly enraged crowds, fed by rumors transported at the speed of light from one Third World megalopolis to another. So in addition to Malthus, we will also hear much about Elias Canetti, the 20th-century philosopher of crowd psychology: the phenomenon of a mass of people abandoning their individuality for an intoxicating collective symbol. It is in the cities of Eurasia principally where crowd psychology will have its greatest geopolitical impact. Alas, ideas do matter. And it is the very compression of geography that will provide optimum breeding grounds for dangerous ideologies and channels for them to spread.

…much of Eurasia will eventually be as claustrophobic as Israel and the Palestinian territories, with geography controlling everything and no room to maneuver. Although Zionism shows the power of ideas, the battle over land between Israelis and Palestinians is a case of utter geographical determinism. This is Eurasia’s future as well.

…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.