And, in what I hope is my last post on foreign policy realism for the day, I think there’s a general problem with the oft-elided distinction between descriptive and prescriptive realism.

Descriptive realism is a theory of how international relations works. Interests drive the behavior of states, not sentiment or ideology. One Arab state may cooperate with the Jewish state against another Arab state; one Christian kingdom with a Muslim kingdom against another Christian kingdom; one Communist dictatorship with a capitalist democracy or fascist dictatorship against another Communist dictatorship – in each case depending on whether their bread is buttered on the relevant side. As such, if you want to predict what a state will do in a given circumstance, or in response to a given policy, examine their objective interests rather than what they declare their regime believes or what are its people’s sentiments and prejudices.

But this descriptive theory necessarily has prescriptive implications. If you believe that interests drive foreign relations, then a policy premised on another theory – that, for example, democracies will not go to war with one another, or that non-democratic regimes that depend on radical ideology are necessarily aggressive, or that alliances of sentiment and ideology are more enduring that alliances of convenience (or, for that matter, that states can effectively be manipulated against their national interests through the application of interest-group-based pressure within the system – a notion that both many supposed realists and some neoconservatives seem to believe far too easily, the difference between them being that some realists assume we are the ones being manipulated, while some neoconservatives assume it’s foreign regimes that we can manipulate effectively in this manner) – will prove itself ineffective in practice.

A state following a policy based on one of these premises will be surprised by unexpected rebuffs and betrayals and outbreaks of conflict, or may commit itself to action unnecessarily based on threats that don’t really exist. Descriptive realism implies, prescriptively, that an effective foreign policy will be crafted based on an understanding that other states will be motivated by a rational assessment of their own national interests. Both threats and opportunities will be assessed accordingly.

What it doesn’t do is say anything about the moral content of our own foreign policy. A given state could, perfectly reasonably, pursue a highly idealistic foreign policy while being guided by descriptive realism. Descriptive realism wouldn’t dictate that state’s goals, but would shape that state’s expectations of how its policy would play out in practice. That state would not assume that other states would recognize that it was pursuing an idealistic foreign policy, and adjust their own foreign policies in gratitude. Rather, it would assume that other states would react to its own idealism by interpreting it in terms of theories about our own assessment of our own national interest, and by evaluating it in terms of its effect on their own interests.

Analogously, the manager of a business could decline to enter a business line she thought unethical or immoral even if legal and profitable, notwithstanding assenting to the general proposition that her job is to maximize shareholder value. She is, after all, a human being in addition to being a manager. She just wouldn’t rationally assume that, because she chose to forego this business opportunity, other firms will do likewise; rather, she should assume that she has just handed a gift to whoever does choose to seize that opportunity.

My point being: descriptive realism does have prescriptive implications, but those implications do not include some kind of obligation to follow a prescriptively realist foreign policy.