The tendency of both the Clinton administration and its Republican opponents to frame foreign policy as a compromise between "global policeman" and "isolationism" misses the point entirely. The real issue is what the United States commits itself to defend--and whether it is actually willing to incur the costs and risks required to fulfill such commitments. Structural changes in the international system already greatly limit the options of U.S. policymakers.
Ostensibly moderate foreign policy doctrines such as "selective engagement" and "new internationalism" are operationally meaningless. They erroneously assume that, to one degree or another, the United States can impose its policy preferences around the world, with acceptable costs and risks. Moreover, advocates of so-called selective engagement would end up endorsing almost all of Washington's current security obligations and recent military interventions, give or take a couple of strategically and budgetarily trivial cases such as Somalia and Haiti.
Attempts to intervene in other regions--especially with ground forces--will become more difficult and dangerous in the 21st century, in the face of emboldened challengers and the defection of U.S. allies and clients. America's competent military can inflict great damage on an adversary, but that capability does not translate into an ability to exercise effective and durable political control in far-flung regions. Instead of continuing the forward deployment and contingent use of its military forces in a vain effort to defend a lengthy roster of client states and maintain an illusory global order, the United States should concentrate on developing strike warfare--long-range retaliatory capabilities--to be used to defend only its indisputably vital interests.