31 know about their capabilities and the situation. They begin taking concrete steps along the path that they think will get them to that end. They learn far too slowly that what they initially thought they knew was in fact wrong or no longer relevant. .. . Things can get much more convoluted by adding allies, different influential actors among the polity, and multiple adversaries. This is why wars are easier to get into than out of.15 Knowing when to end a war relates to war aims and measures of success. A war’s aims should be definitive enough so that success can be measured in some clear way. This is easiest to do where the aims concern discrete things such as the destruction of material targets. Measuring success becomes harder as aims become more political and psychological, such as weakening or toppling a regime, encouraging opposition or deterring further action. Then, too, war aims can expand as fighting escalates or broadens. In a situation in which Iran has retaliated strongly and managed to inflict losses (especially civilian losses) on the United States or its coalition partners, we should expect to hear calls to inflict more damage, to punish the regime and its forces, to bring a “decisive” end to the conflict. Short of inflicting a total defeat on Iran, an outcome that seems scarcely conceivable, exiting the war could be challenging if Iran chooses to fight on in some form of asymmetric conflict. We might then have to compel Iran to quit, and that could potentially require the application of force well beyond what was originally agreed upon within the United States or with coalition partners. Even then, if the Iranian regime survives at all, it is likely to declare victory, and many of its supporters would believe it. How or when a war with Iran would actually end is therefore no easy topic to nail down. Any attack on Iran of sufficient scale to significantly damage its nuclear program would have rolling consequences both in the short and long term. H