The OPEC often described as a cartel, it is better seen as an anti-glut group. When demand is weak, its members can curb production to prevent the price plummeting. But when demand is healthy, its ability to curb new producers is limited. And new producers abound.

America’s domestic production of crude (and gas, which displaces some oil) is rocketing. The IEA says the country will produce 14m barrels a day (b/d) next year, on a par with Saudi Arabia . That has reduced America’s imports, as well as boosting exports of fuels (exports of crude oil are mostly banned). That frees crude from other places, such as West Africa, to go to Europe instead. Similarly, Latin American and Middle Eastern oil that once would have gone to America now goes to Asian customers.

For the oil-rich, even worse is in store. Other factors that have propped up the price over the past decade are likely to wane in importance. Even the slightest easing of sanctions helps Iran, potentially a huge producer….The Economist Intelligence Unit…forecasts a “significant boost” in 2014 from 2.4m b/d last year. This assumes new investment pays off, and a deal with the semi-autonomous Kurdish region. Libya could be another source of production: its exports have collapsed to only a few hundred thousand barrels a day, against 1.6m in June last year…

An alternative for Saudi Arabia would be to increase production sharply. That would send the price down: painful for the kingdom, but even more painful for higher-cost producers (not least America, where the “tight oil” now coming on stream requires prices of $50 and above to be profitable).  OPEC’s best hope is continued American protectionism. Any easing of the restrictions on the export of liquefied natural gas (LNG) or crude will exert more downward pressure on the oil price. That might be good for the world economy, but it is not a priority for American consumers, who would like cheaper petrol for cars and propane for heating…

OPEC and oil prices: Leaky barrels, Economist, Feb. 22, 2014, at 63