A couple decades ago, "smart power" was all the rage in U.S. foreign policy discussions, largely in response to the perceived foolishness of the administration of then-U.S. President George W. Bush for having become bogged down in two overseas wars. Advocates of smart power used those failed interventions to point to the limitations of hard-power instruments - like military and economic coercion - for achieving foreign policy goals. The idea of smart power seems especially relevant to foreign policy discussions in what I last week called "the era of great power stupidity." But what exactly is meant by a smart foreign policy? That's not an easy question to answer, and that tells us a lot about the making of foreign policy in general. One place to start would be to identify desirable outcomes and ask whether the policies chosen by decision-makers will achieve them. In the foreign policy realm, peace and prosperity seem like clearly desirable outcomes. So if a government's policies bring about peaceful relations with other countries and make its country wealthier, then they must be smart policies. Right? Not necessarily. Foreign policy choices don't often boil down to "choose war or peace" or "choose prosperity or poverty." Instead, in many instances the "right" foreign policy choice is not obvious. Moreover, peaceful outcomes are not always the result of the situation having been smartly handled. Flukes, even positive ones, happen. Sometimes a policymaker just gets lucky. For instance, while U.S. policymakers attributed the peaceful end of the Cold War to their own astute policies, the collapse of the Soviet Union was largely due to structural factors that were outside the control of even the most skilled policymaker. Rather than specifying desirable outcomes, another way to determine if a foreign policy is smart is to consider the idea of "rationality," which is often invoked by international relations scholars. A simple variant of this idea holds that rational governments do indeed pursue policies that maximize national wealth and citizen wellbeing. But as discussed above, that is a difficult criterion to apply. A slightly more sophisticated version holds that rational governments make use of all available information when setting policies. But of course, no government can possess all possible information, and all governments face limits in their ability to process the information that is available to them. Instead of using rationality to mean simply achieving "good outcomes" or "using all information" when making foreign policy decisions, we can alternatively use it to refer to whether decision-makers pursue a course of action consistent with whatever outcome they want to achieve. Regardless of what that outcome is, does the decision-maker act in a way that maximizes the chances of getting it? For example, take Russian President Vladimir Putin's decision to invade Ukraine. If his goal was to ensure that Kyiv is unable to exercise its full sovereignty and disrupt European security, for now, at least, he has achieved his objective. You can argue that his goal is unreasonable, immoral and even stupid, but that doesn't mean it's not rational. The fact that a foreign policy decision is rational alone doesn't help us determine if it is smart. Here it helps to think again of the circumstances that led to the emergence of "smart power" as a concept: the U.S. invasion of Iraq in 2003. The Bush administration seemed determined to invade Iraq no matter what Saddam Hussein did, no matter what information was available and no matter what criticism its invasion drew internationally. That now clearly appears to have been foolish. But whether it was necessarily irrational depends on the goal. If the goal was simply to remove Saddam, it was both rational and successful, as the means achieved the desired end. Similarly, if it was to send a message to others that the U.S. cares so much about preventing nuclear proliferation that it will enga...