Grand strategy
With this in mind, some supporters of this strategy argue that the U.S. should work to contain China and other competitors rather than engage them. In regards to humanitarian crises and regional conflicts, primacy holds that the U.S. should only intervene when they directly impact national security, more along the lines of selective engagement than collective security. It does, however, advocate for the active prevention of nuclear proliferation at a level similar to collective security.
Implementation of such a strategy would entail military forces at similar levels to those during the Cold War, with emphasis on military modernization and research and development. They note, however, that "the quest for primacy is likely to prove futile for five reasons": the diffusion of economic and technological capabilities, interstate balancing against the United States, the danger that hegemonic leadership will fatally undermine valuable multilateral institutions, the feasibility of preventive war and the dangers of imperial overstretch.
Daniel Drezner, professor of international politics at Tufts University, outlines three arguments offered by primacy enthusiasts contending that military preeminence generates positive economic externalities. "One argument, which I label 'geoeconomic favoritism,' hypothesizes that the military hegemon will attract private capital because it provides the greatest security and safety to investors. A second argument posits that the benefits from military primacy flow from geopolitical favoritism: that sovereign states, in return for living under the security umbrella of the military superpower, voluntarily transfer resources to help subsidize the cost of the economy. The third argument postulates that states are most likely to enjoy global public goods under a unipolar distribution of military power, accelerating global economic growth and reducing security tensions. These public goods benefit the hegemon as much, if not more, than they do other actors." Drezner maintains the empirical evidence supporting the third argument is the strongest, though with some qualifiers. "Although the precise causal mechanism remain disputed, hegemonic eras are nevertheless strongly correlated with lower trade barriers and greater levels of globalization." However, Drezner highlights a caveat: The cost of maintaining global public goods catches up to the superpower providing them. "Other countries free-ride off of the hegemon, allowing them to grow faster. Technologies diffuse from the hegemonic power to the rest of the world, facilitating catch-up. Chinese analysts have posited that these phenomena, occurring right now, are allowing China to outgrow the United States."

Primacy vs. selective engagement: Barry Posen, director of the Security Studies Program at the Massachusetts Institute of Technology, believes the activist U.S. foreign policy that continues to define U.S. strategy in the twenty-first century is an "undisciplined, expensive, and bloody strategy" that has done more harm than good to U.S. national security. "It makes enemies almost as fast as it slays them, discourages allies from paying for their own defense, and convinces powerful states to band together and oppose Washington's plans, further raising the costs of carrying out its foreign policy." The United States was able to afford such adventurism during the 1990s, Posen argues, because American power projection was completely unchallenged. Over the last decade, however, American power has been relatively declining while the Pentagon continues to "depend on continuous infusions of cash simply to retain its current force structure—levels of spending that the Great Recession and the United States' ballooning debt have rendered unsustainable."
Posen proposes the United States abandon its hegemonic strategy and replace it with one of restraint. This translates into jettisoning the quest of shaping a world that is satisfactory to U.S. values and instead advances vital national security interests: The U.S. military would go to war only when it must. Large troop contingents in unprecedentedly peaceful regions such as Europe would be significantly downsized, incentivizing NATO members to provide more for their own security. Under such a scenario, the United States would have more leeway in using resources to combat the most pressing threats to its security. A strategy of restraint, therefore, would help preserve the country's prosperity and security more so than a hegemonic strategy. To be sure, Posen makes clear that he is not advocating isolationism. Rather, the United States should focus on three pressing security challenges: preventing a powerful rival from upending the global balance of power, fighting terrorists, and limiting nuclear proliferation.
John Ikenberry of Princeton University and Stephen Brooks and William Wohlforth, both of Dartmouth College, push back on Posen's selective engagement thesis, arguing that American engagement is not as bad as Posen makes it out to be. Advocates of selective engagement, they argue, overstate the costs of current U.S. grand strategy and understate the benefits. "The benefits of deep engagement...are legion. U.S. security commitments reduce competition in key regions and act as a check against potential rivals. They help maintain an open world economy and give Washington leverage in economic negotiations. And they make it easier for the United States to secure cooperation for combating a wide range of global threats."
Ikenberry, Brooks, and Wohlforth are not convinced that the current U.S. grand strategy generates subsequent counterbalancing. Unlike the prior hegemons, the United States is geographically isolated and faces no contiguous great power rivals interested in balancing it. This means the United States is far less threatening to great powers that are situated oceans away, the authors claim. Moreover, any competitor would have a hard time matching U.S. military might. "Not only is the United States so far ahead militarily in both quantitative and qualitative terms, but its security guarantees also give it the leverage to prevent allies from giving military technology to potential U.S. rivals. Because the United States dominates the high-end defense industry, it can trade access to its defense market for allies' agreement not to transfer key military technologies to its competitors."
Finally, when the United States wields its security leverage, the authors argue, it shapes the overall structure of the global economy. "Washington wins when U.S. allies favor [the] status quo, and one reason they are inclined to support the existing system is because they value their military alliances."
Ted Carpenter, senior fellow at the Cato Institute, believes that the proponents of primacy suffer from the "light-switch model," in which only two positions exist: on and off. "Many, seemingly most, proponents of U.S. preeminence do not recognize the existence of options between current policy of promiscuous global interventionism and isolationism." Adherence to the light switch model, Carpenter argues, reflects intellectual rigidity or an effort to stifle discussion about a range of alternatives to the status quo. Selective engagement is a strategy that sits in between primacy and isolationism and, given growing multipolarity and American fiscal precariousness, should be taken seriously. "Selectivity is not merely an option when it comes to embarking on military interventions. It is imperative for a major power that wishes to preserve its strategic insolvency. Otherwise, overextension and national exhaustion become increasing dangers." Carpenter thinks that off-loading U.S. security responsibility must be assessed on a case-by-case basis. Nevertheless, the United States must refrain from using military might in campaigns that do not directly deal with U.S. interests. "If a sense of moral indignation, instead of a calculating assessment of the national interest, governs U.S. foreign policy, the United States will become involved in even more murky conflicts in which few if any tangible American interests are at stake."

Today: Posen has argued that the four schools of U.S. grand strategy that he identified in the 1990s have been replaced by just two: liberal hegemony, which came from a fusion of primacy and cooperative security, and restraint, which came from a fusion of neo-isolationism and selective engagement. Other scholars have proposed a third policy, offshore balancing.

Liberal hegemony: Proponents of liberal hegemony favor a world order in which the United States is a hegemon and uses this power advantage to create a liberal international system and at times use force to enforce or spread liberal values (such as individual rights, free trade, and the rule of law). The United States strives to retain overwhelming military power, under a theory that potential competitors will not even try to compete on the global stage. It also retains an extensive network of permanent alliance commitments around the world, using the alliance system both to advance and retain hegemonic power and to solidify emerging liberal political systems. According to Posen, this strategy sees "threats emanating from three major sources: failed states, rogue states, and illiberal peer competitors." Failed states, in this view, are sources of instability; rogue states can sponsor terrorism, acquire weapons of mass destruction, and behave unpredictably; illiberal peer competitors would compete directly with the United States and "would complicate the spread of liberal institutions and the construction of liberal states." Support for liberal hegemonic strategies among major thinkers in both political parties helps explain the broad elite support for the 2003 invasion of Iraq and the 2011 intervention in Libya, even though U.S. military involvement in those conflicts had been initiated by presidents of different parties. The chief difference on foreign policy between Republican and Democratic proponents of liberal hegemony, according to Posen, is on support for international institutions as a means to achieving hegemony.

Restraint: Proponents of a grand strategy of restraint call for the United States to significantly reduce its overseas security commitments and largely avoid involvement in conflicts abroad.