But think of the multipolar chess President Obama is now playing. Every country involved in the dispute over Iran’s possibly acquiring nuclear weapons is calculating how the American presidential election plays to its agenda. The politics of soaring oil prices loom over any threat of military conflict, even a brief skirmish in the Strait of Hormuz. And with global economic turmoil a reality and leadership changes possible or certain this year in the United States, Russia, China and France, the game gets even more complex.

Start with the Iranians themselves. They have studied China’s example, and the case of Pakistan, which faced severe economic sanctions — urged foremost by the United States — for its pursuit of the bomb. But in both cases, once those countries conducted a test, the world adjusted to the new reality. Less than a half century later, China is the world’s second largest economy, and no one messes with it. As soon as the Sept. 11 attacks happened, the sanctions against Pakistan disappeared; suddenly the United States cared about cooperation in hunting down Al Qaeda more than it cared about Pakistan’s dangerous export of bomb technology, including to Iran.

“From the perception of the Iranians, life may look better on the other side of the mushroom cloud,” said Ray Takeyh, a senior fellow at the Council on Foreign Relations. He may be right: while the Obama administration has vowed that it will never tolerate Iran as a nuclear weapons state, a few officials admit that they may have to settle for a “nuclear capable” Iran that has the technology, the nuclear fuel and the expertise to become a nuclear power in a matter of weeks or months.