A. 级 The U.S. and Iran don't agree on much these days. But in their conflict over Iran's nuclear program, both seem willing to use oil as a political weapon. The U.S. believes that sanctions on Iran's energy exports might force Tehran to renounce its uranium-enrichment ambitions. Iran hopes its threats to withhold some of those exports will persuade the international community to back off. One thing is certain: a substantial reduction in Iran's energy output would have a significant impact on global oil prices. Iran is the fourth-largest oil exporter in the world. It sells more than 2.5 million barrels a day. Many analysts say a supply cut could drive prices up to $g0 to $100 a barrel. Some analysts argue that it is less dangerous for the U.S. to simply accept a nuclear Iran than to risk the damage that sharp Iranian production cuts--or Iranian retaliation against a U.S. or Israeli military strike--might do to U.S. interests. After all, Iran is unlikely to ever fire a nuclear missile, which could be expected to respond in kind. But the Bush administration fears that Iran might sell nuclear material to other states, and possibly to terrorist groups. It's also concerned that other Middle Eastern countries might feel compelled to go nuclear. The U.S. will continue over the next several weeks to try to push sanctions through the Security Council. But the council is increasingly unlikely to impose them. Russia has extensive trade ties with Iran, and it can veto any resolution.