(Warning: for IR geeks only)
Back in the 1990s, the International Relations subfield of Political Science was consumed by the so-called "rationalism-constructivism" debate. Constructivism argued that mainstream Realist, Liberal, and formal modeling approaches to IR drastically under-stated the role of ideas, discourse, and identities in explaining political behavior. (*) Constructivists attempted to demonstrate that identities, ideas, and discourse mattered even in the 'heartland' of security studies (as in this influential volume edited by Peter Katzenstein, or in this volume on the Middle East edited by Mike Barnett and Shibley Telhami). Many Realists countered that these 'soft' and 'fuzzy' factors mattered only at the margins, or in relatively insignificant areas of political life: if ideas or moral norms mattered, it was only because of the strategic insignificance of the issue, or because the norms coincided with the interests of powerful states (as in this influential rejoinder written by Michael Desch). While this debate was never fully resolved (are they ever?), many saw the possibility for a synthesis by using Stephen Walt's 'balance of threat' ideas, or Realist models incorporating domestic politics.
The Realist-constructivist debate was somewhat overtaken by another, parallel debate between constructivists and "rationalists" - sometimes referring to those who analyzed international relations in formal terms, taking identities and interests as given in order to model strategic interaction, and sometimes referring more broadly to those who emphasized material power considerations (whether Realist or Liberal) over ideational or cultural variables. That debate seemed to reach a tentative resolution with an article jointly written by the leading rationalist James Fearon and the leading constructivist Alex Wendt which basically argued that rationalism and constructivism could easily co-exist, because it was primarily a methodological distinction rather than a substantive one. Realism and Liberalism differed substantively over the value of international institutions, or containment vs engagement strategies, or the priority of military vs economic conceptions of the national interest.... and thus offered clearly different policy advice. Rationalism vs constructivism, by this argument, did not have such substantive differences and as such could not constitute a comparable 'Great Debate.' Indeed, a synthesis could easily be imagined: constructivists might explain the identities and interests of the actors, which would allow rationalists to model a specific episode of strategic interaction (see Lynch 2002, for another take on a potential rationalist-constructivist synthesis).
Constructivism has won, at least in the security policy realm. The key tenets of its research program have become the conventional wisdom in the public realm: that ideologies and ideas (such as Islam) matter, that the significance of ideas can not be reduced to material power, that norms (such as a norm against terrorism) matter, that public arguments and discourse (such as Muslim condemnations of terror, or the 'war of ideas') matter. Given that constructivism was long dismissed as too soft and fuzzy, insufficiently rigorous, and lacking in policy relevance, this has to be a surprising outcome (but see my note at the bottom of this post).
Take al-Qaeda. It has long since become conventional wisdom that al-Qaeda is a non-state actor (contra Realism) motivated by a powerful Islamist ideology (contra rationalism). Its members are willing to die for these ideas. The main line of debate is not about whether or not its ideas matter for explaining its behavior. The debate is over whether al-Qaeda action is fully expressive and completely non-strategic (killing for the sake of killing, irrational hatred of the West unrelated to specific policies, self-actualization to get to heaven), or else strategically rational within the bounds of its worldview (specific actions aimed at producing specific results, to influence the target or a watching audience).
This is a debate fully defined in constructivist terms. The 'strong' case (fully expressive action) eliminates material considerations and rational strategy completely; the 'weak' case falls exactly within the Wendt-Fearon synthesis (rational action within a 'game' defined by the identities, discourses, and beliefs of the actors). Accepting the constructivist approach here, I hasten to repeat, does not mean accepting the 'expressive' account which denies strategic rationality to al-Qaeda: it could also mean that understanding al-Qaeda's strategy requires understanding its worldview, what it sees as important, the casual links which it assumes between action and outcome.
The American 'war of ideas' response fairly self-evidently takes ideas seriously. For Realists, ideas shouldn't matter this much. The 'war of ideas' also gets to the heart of the rationalism- constructivism debate. Encouraging Muslim condemnations of terrorism follows what Thomas Risse called "the logic of appropriateness". The public argument about terrorism is not about determining the distribution of benefits, or about material power... it's about moral argument and establishing what is appropriate behavior for those who identify as Muslims.
A central strategy in the "war on terror" is the creation of a norm against terrorism. Norm-creation was one of the key strands of constructivist research (Martha Finnemore and Kathryn Sikkink). Realists (and hawks) argued bitterly against the relevance of such norms. Trying to build a norm against terror concedes the point against which Realists and (some) rationalists fought for so long: norms matter. Otherwise, why bother? And if you want to know how to go about building an international norm, constructivists are the place to turn.
Most popular understanding - and, I think, serious policy analysis - now rests on a constructivist account of political identity, of the relationship between identity and norms, and of the nature of political power. Identities are fluid, not fixed; interests do not follow obviously from material conditions; norms of appropriateness have a significant impact on political behavior; and real power flows from the ability to define such norms.
Hence, the war of ideas: Al-Qaeda is trying to mobilize the Islamic umma against the West, explicitly aiming to manufacture a collective identity (Islamic) and to define the 'interests' which logically and necessarily follow from that identity. If they succeed in establishing this norm, then violence against the West - a defensive jihad - becomes normatively appropriate. Al-Qaeda's opponents are trying to establish a norm that terrorism is wrong: morally unjustifiable and politically unacceptable. What policy makers need to know is how to create such a norm, what strategies are likely to work and which will fail.
This is constructivism through and through... albeit a constructivism shot through with considerations of power, well stripped of jargon, and one whose policy relevance can no longer be denied.
Why did constructivism win? Well, partly because it provided a more accurate and useful picture of the world, I think. Because it took ideas and transnational forces and global norms seriously at a time when those leapt to the fore of foreign policy concerns. But also partly because - and here I go out even further on a limb - at least some of the neo-cons in the Bush administration are really constructivists, whether they admit it or not. Like constructivists, and unlike Realists, they believe that ideas matter, they believe in moral argument (at least for public consumption), they believe in the possibility of progressive change (spreading democracy). That's why so many Realists opposed them.
I think that most constructivists opposed the neo-con agenda in spite of this because the neo-con methods were so spectacularly at odds with those that they advocated: working against rather than with global civil society, lecturing from a moral high ground rather than taking other seriously in dialogue, denigrating the UN and international law, invading Iraq without the UN or a global consensus behind them. I think that this mismatch between goals and methods explains a lot of Bush's failures - why "shock and awe" failed to win over Arab public opinion, for example, or why it failed to win legitimacy for the Iraqi campaign and why that failure mattered so much. But unlike the rationalist-constructivist or Realist-constructivist debates, the neocon-constructivist debate is really an intra-constructivist argument... if only the constructivists would recognize it as such and join in.
(NOTE: lightly edited version of something written for another purpose. Trust me, I know that nobody really cares about this!)
(NOTE: as some readers no doubt know, I am an IR constructivist, who has over the years taken some ribbing from policy-oriented friends for 'all that Habermas shit'. This declaration of constructivist victory should therefore be taken as a provocation... one which hopefully will generate some fun dissent!)