Obama’s stance implies that we have no choice but to accept Iran’s best offer — whatever is, to use Rice’s term, “achievable” — because the alternative is unthinkable.

But should it be? What if force is the only way to block Iran from gaining nuclear weapons? That, in fact, is probably the reality. Ideology is the raison d’etre of Iran’s regime, legitimating its rule and inspiring its leaders and their supporters. In this sense, it is akin to communist, fascist and Nazi regimes that set out to transform the world. Iran aims to carry its Islamic revolution across the Middle East and beyond. A nuclear arsenal, even if it is only brandished, would vastly enhance Iran’s power to achieve that goal.

Such visionary regimes do not trade power for a mess of foreign goods. Materialism is not their priority: They often sacrifice prosperity to adhere to ideology. Of course, they need some wealth to underwrite their power, but only a limited amount. North Korea has remained dirt poor practicing its ideology of juche, or self-reliance, but it still found the resources to build nuclear weapons.