Here's a question for you: does it make sense for the United States to open its best universities to students from China (or any other potential long-term rival) and to help them to acquire advanced scientific and technical knowledge?
On the plus side, you could argue that all universities ought to admit the best and brightest applicants no matter where they come from, because that will help these universities do better work. Having smart students is a powerful spur to continued progress, no matter where they come from. Moreover, this practice might help the United States cream off some of the best foreign talent by convincing them to remain here after they graduate, where they will be of great benefit to the U.S. economy. And even if some of the best foreign students get trained here and then go back home, they can help their own societies develop, generate economic growth, and create bigger markets for everyone, so that the whole global economy grows and we all benefit.
But the downside is obvious too: if more and more of these well-trained people head back home, then U.S. universities will be transferring knowledge that might reduce America's comparative advantage. Even worse, we might be making it easier for other states to catch up or eventually surpass us in areas of advanced technology that have military implications (including cyber-security). So maybe we ought to be limiting foreign access to U.S. higher education, in order to preserve our own advantages for as long as we can.
There, in a nutshell, is a key difference between realists and liberals. Although the latter concede that there is a competitive element to world politics, they tend to downplay it and to focus primarily on the gains to be had from mutual cooperation. This tendency is evident in the emphasis placed on "engaging" China, which has been a hallmark of U.S. policy since the Clinton administration. This view stresses the need for cooperation and the benefits that the United States (and others) will gain as China becomes wealthier, and one dimension of that would be opening up U.S. institutions of higher education and collaborating with Chinese universities.
By contrast, realists tend to worry more about long-term shifts in the relative balance of power between the two sides, and warned that enabling Chinese growth could eventually place the United States in a position where its own influence is reduced. If you believe that Sino-American rivalry will be hard to avoid and potentially costly, then you'd want to start think hard about ways to slow China's rise. But nothing is cost-free: taking steps like that could reinforce Chinese suspicions-- duh! -- and at a minimum means consigning millions of Chinese citizens to lower standards of living. And guess what? It would probably also reduce U.S. standards of living too, although perhaps not by as much.
Here's one way to think about these starkly contrasting worldviews. For liberals, world politics is like playing music, and states are just like members of a band or orchestra. Making good music requires teamwork and cooperation, and the quality of the music generally improves the more highly skilled the musicians are. Among other things, this means that helping your fellow players improve is good for the group as a whole; if your bass player or drummer gets better, then the overall group sound gets better too. So members of a band or an orchestra should help each other out, and not worry about whether one player is improving faster than the others are. And while there can be elements of rivalry or jealousy within a band (or between different groups), it's usually not a zero-sum activity. If La Scala improves and makes opera more popular, that's good for the Met; just as the Beatles and other English groups kicked the door open for lots of other bands too. Similarly, if Wynton Marsalis becomes famous and reignites interest in jazz, then other jazz musicians benefit too.
Musicians obviously have to agree on what piece of music to play, and it helps to have rules to guide them, whether it's fully orchestrated score, a lead sheet, or even just a loose arrangement with a list of solos. Even more abstract forms of improvised jazz depend on hours of training and a shared understanding of musical language. Such norms or rules or tacit understandings facilitate cooperation, and make it possible for lots of individuals to play together without a lot of prior rehearsal.
Thus, music is a pretty good metaphor for the liberal view of world politics, which is why liberals emphasize the importance of international law, institutions, and hegemonic leadership. And that's why most American liberals like to talk about the indispensability of the United States: in their view, the world orchestra needs a conductor, and who is better positioned to play that role than Washington DC? But the underlying image is still one where all will be better off if they work together; and where everyone has a common interest in helping others improve. No wonder E.H. Carr famously characterized idealist (i.e., liberal) approaches as emphasizing the "harmony of interests."
By contrast, realists see international politics as less like music and more like sports. We're not talking about exquisite harmonies and seamless group dynamics; we're talking NFL football or World Cup Rugby. There are clear winners and losers, the competitors sometimes cheat, and athletes are fools if they spend any time helping rivals improve. Players have an interest in helping teammates get better, but you wouldn't expect Albert Pujols of the St. Louis Cardinals to be giving hitting tips to a member of the Texas Rangers right now, and you wouldn't expect Roger Federer to call up Andy Murray and offer him some advice on how to improve his serve.
Unlike music, the essence of sports is inherently competitive, and the winners normally get a lot more benefits than the also-rans do. Rules exist to define the nature of the competition, but everyone understands that some people might cheat. By comparison, it's not even clear what it would mean to "cheat" when you're trying to play music, or how "cheating" would be of any benefit.
So which view provides a better metaphor for world politics? Although both metaphors can offer some revealing insights, it won't surprise you to learn that I think foreign policy is a lot more like sports than it is like music-making. Even if states can gain from collaboration, the benefits of collaboration are not evenly distributed and relative power still matters. More importantly, the occasional periods of close cooperation are occasionally disrupted by all-out struggles that redistribute power and leave the winners better off and the losers licking their wounds. When that occurs, of course, the rules tend to fall by the wayside. Imagine an NFL game played for high stakes, and with no referees on the field.
And because states now that such struggles can occur at any time, the possibility casts a grim shadow over much of their behavior.
Finally, let's not forget that relative power matters in the supposedly collaborative world of music. Conductors and bandleaders (and sometimes financial backers) get to decide what pieces to feature, and minor players just play what they are told. It was Duke Ellington's orchestra, not Johnny Hodges', and there's a reason why most of the songs on the Beatles' albums are by Lennon or McCartney and not George Harrison or Ringo. Over time, changes in the distribution of power world-wide will determine who gets to call the tune, and we might want to think about that before the set list changes in ways we might not like.
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