Until cars and trucks can be powered by solar, wind, or nuclear energy, the entire world depends on the free flow of oil from the Persian Gulf region. That requires American security guarantees, which require our presence. And until radical Islamist organizations utterly lose their local appeal, we’ll have little choice but to intervene periodically for reasons that have nothing to do with economics or resources. For the time being, aggravating though it may be, Americans and Arabs are stuck with each other. We can take a bit of a breather, but retirement is decades away.