As I've discussed previously, United States foreign policy generally breaks down into three schools of thought: primacists, liberal internationalists, and realists. All three share a basic commitment to U.S. engagement in the world. A fourth school, primarily relegated to academia, advocates for a significant shift in U.S. policy away from extensive foreign engagement. Refining the traditional American isolationist impulse into a more coherent and comprehensive policy, this approach is termed retrenchment.
In brief, retrenchment would entail a withdrawal of U.S. military forces from overseas deployments, allowing the United States to significantly cut its defense budgets while also avoiding the types of foreign entanglements that inspire resentment and hostility. Economic and trade relations with the rest of the world would continue as they exist today but allies in Europe and East Asia would be responsible for their own security. Assuming that states ally with others to "balance" against potential threats, the rest of the developed world should be capable of sorting out their own problems without the United States. Regional orders will ultimately emerge and the world will be stable.
The most difficult challenge for the retrenchment school relates to the assumption that states will effectively balance against threats. The history of international relations repeatedly provides examples of two distinct critical flaws in this assumption. First, states may fail to balance in time to deter a threat (think England, France and the Soviet Union before World War II) and second, some leaders may not be deterred (Louis XIV, Napoleon, Hitler). Retrenchment advocates seem to acknowledge these problems, but argue that the United States would likely have the time to aid former allies against emerging threats, and could engage in "offshore balancing" to reinforce stability in a given region rather than maintain costly overseas commitments.
It is sometimes easy to forget (but important to underscore) that the United States effectively ensures the security and stability of critically important regions. In Europe, the presence of U.S. forces in NATO has contributed to a secure, stable regional system despite the collapse of the Soviet Union, German reunification, and European integration. In East Asia, U.S. security guarantees and forward deployed forces have contributed to the emergence of a vibrant economic system. Even China benefits from the U.S. presence, as it doesn't have to fear an independent Japanese foreign policy, or the potential for instability and conflict on the Korean peninsula. The removal of U.S. forces from regions like Europe and East Asia could easily lead to instability and the increased potential for crisis. Given the benefits that the United States receives from its engagement in these regions, the potential costs and risks of withdrawal must be weighed alongside any expected benefits of "coming home."
Unsurprisingly, the retrenchment school has found few advocates in mainstream American politics. Given the sacrifice in blood and treasure that the United States has made over the past century in Europe and Asia, and more recently in the Middle East, simply pulling back and letting the rest of the world carry on is difficult to accept. A more idealistic view would argue that the United State remains an indispensable nation, and when the United States is not engaged is when bad things are most likely to happen in the world. A more cynical view may argue that the domestic economic interests related to a large, globally-capable military and the concerns of multinational corporations abroad would foreclose any such attempt to truly move the nation toward retrenchment. Simple policy inertia and a reticence to significantly alter what seems like a generally positive and stable global situation may also play a role. In fact, all of these views may have some resonance with an American audience.
Nonetheless, if after an extensive national debate, retrenchment indeed became the long-term policy of the United States, Washington could (at the very least) develop meticulous plans and actively work with its partners on effective implementation. Important tasks would likely include the gradual withdrawal of U.S. military forces from key regions, the turnover of critical infrastructure to allies, and the initiation and implementation of confidence building measures to dampen any potential problems that may arise. Nevertheless, these measures--no matter how well devised or implemented -- may not be enough. In short, inertia may continue to keep the United States engaged in the world, but it is not difficult to envision the real risks and potential costs of a U.S. withdrawal from the world stage.
Amidst the current dysfunctional debates taking place in Washington, little mention has been made of America's global commitments. But given the rise of a political force that fundamentally distrusts government and seeks to limit its capabilities and resources, perhaps foreign policy deserves more attention. Taking to its logical conclusion, the platform of the so-called Tea Party members in the U.S. Congress will have significant negative effects on the ability of the United States to continue to play its leadership role in world politics. This may be their objective: to rekindle the isolationist impulse that has faded from mainstream American politics. If so, retrenchment must be presented as a coherent policy, understanding the potential repercussions of such a major shift in U.S. strategy. However, if there is no coherent worldview and Tea Party foreign policy seeks to simply maintain America's position in the world while purposefully eroding the foundations of its power, then the long-term security of the United States is in serious jeopardy.