Ilan Goldenberg writes that one reason academic realists have become marginalized in policy debates is that politicians think a policy of restraint isn’t politically feasible:
These days the realist perspective is all but non-existent in Washington. A large part of that has to do with the fact that their ideas are so politically unpopular that they are simply dismissed out of hand as unrealistic. Many realists have come to the conclusion that as an unfettered unipolar power the United States will inevitably overextend itself and scare others into aligning against it, and thus over time weaken itself. The best prescription for this is retrenchment that includes dramatic reductions in military spending and the reduction of our presence around the world — very politically unpopular ideas.
These two formulations are slightly different, and I think it’s important to distinguish between them. The public doesn’t tend to have detailed views on foreign policy issues, but it’s generally sympathetic to the idea of more restrained foreign policy. The Chicago Council on Global Affairs does a regular biannual survey of the American public, and the 2008 edition found “that a strong majority of Americans (63%) want the United States to play an active part in world affairs” but also that “as Chicago Council polls have found in the past, Americans do not want to play the role of world policeman, with 77 percent believing the United States is playing this role more than it should be.”
There can, however, be other kinds of political impediments besides public opinion. The congressional politics of a restrained defense budget are terrible, because the main projects are deliberately located in the districts of the key committee members. The incentives of the news media tend toward amplifying hysteria and overreactions when specific incidents emerge. Presidents tend to be biased toward foreign policy activism because they can play a more unrestrained hand in that field than they can on their domestic issues. And virtually all the key interest groups working on national security policy do so in order to advocate a forward-leaning posture.
And beyond all this, elite opinion in the United States is much more gung-ho about foreign involvements of various kinds than is the public at large. So there’s a lot going on besides popularity. And foreign policy is hardly the only issue on which that’s the case. Big-time politicians have pretty good reasons for not making single-payer health care the core of their domestic policy agenda, but those reasons aren’t really about what’s “popular,” they’re about what’s possible in a constrained system.