The main effect of this is on the riskiest and most vulnerable bits of the oil industry. These include American frackers who have borrowed heavily on the expectation of continuing high prices. They also include Western oil companies with high-cost projects involving drilling in deep water or in the Arctic, or dealing with maturing and increasingly expensive fields such as the North Sea. But the greatest pain is in countries where the regimes are dependent on a high oil price to pay for costly foreign adventures and expensive social programmes. These include Russia (which is already hit by Western sanctions following its meddling in Ukraine) and Iran (which is paying to keep the Assad regime afloat in Syria). Optimists think economic pain may make these countries more amenable to international pressure. Pessimists fear that when cornered, they may lash out in desperation.