2 Underwriting a Strategy of Leadership In the aftermath of World War II, a broad consensus emergedamong Americans that the nation could no longer accept the risksof a strategy that eschewed engagement in the security afairs ofkey parts of Eurasia. History’s most destructive confict showedthat the security and well-being of Americans could only be assuredthrough active engagement abroad and that a priority goal of thatengagement had to be to ensure that no powerful hegemon gaineddominance over the Eurasian landmass.3 With the adoption by theSoviet Union of a hostile, militarized, and expansionist approachto international relations, implementing this strategy led to theadoption by Washington of a strategy of containment by means ofa U.S.-led Western alliance. Tat strategy featured the forward sta- tioning of upward of 500,000 U.S. military personnel abroad. Overtime, the U.S. military alliances with the industrialized democra- cies evolved into a dense web of relationships that encompassedpolitical, economic, technological, and cultural dimensions. Tat strategy of engagement and leadership survived thecollapse of the Soviet Union and the end of the Cold War. By theearly 1990s, it was widely recognized that, in an increasingly inter- dependent world, Americans could not hope to achieve securityand prosperity at home without the ability to infuence actors andshape events abroad. Whether the goal is to protect Americansfrom terrorist threats, to limit the proliferation of weapons ofmass destruction, to ensure adherence to fair trade practices, or toprotect the environment, real progress will require the participa- tion and support of a broad range of international actors. No state,no matter how powerful, can achieve these objectives unilaterally.Given the continued global difusion of knowledge, technol- ogy, wealth, and other instruments of agency, and the increasingconnectedness of the global economy, this reality is not going tochange. It is not unreasonable, then, to expect that U.S. nationalsecurity strategy will continue to be animated by the realiza- tion that no realistic alternative to international engagement andleadership exists, rhetoric touting an “America frst” approachnotwithstanding.4 Under these circumstances, what sort of armed forces shouldthe United States have Te frst strategic priority should be tomaintain peace and stability in regions where the nation has impor- tant interests and alliance commitments that are under stress: EastAsia and Europe. Tis means that the frst military priority is toensure the viability of key alliances and to prevent any state withinterests hostile to those of the United States and its allies fromgaining a position of overwhelming dominance in those regions.5In practical terms, this means today that U.S. forces must be pos- tured to deter aggression by China, Russia, and North Korea and,Whether the goal is to protect Americans from terrorist threats, to limit the proliferation ofweapons of mass destruction, to ensure adherence to fair trade practices, or to protect theenvironment, real progress will require the participation and support of a broad range ofinternational actors. 3 in conjunction with allies and partners, to defeat such aggressionshould deterrence fail.6 In addition to deterring and defeating large-scale aggression bystate adversaries, U.S. forces must also continue, for the indefnitefuture, their campaign against violent extremist organizations, suchas ISIS and al Qaeda, that have the potential to attack U.S. citizensor to destabilize countries or regions of importance to U.S. inter- ests. As the fght to date against terrorist groups shows, long-termsuccess depends on keeping the group’s leaders and networks underunrelenting pressure and building the capabilities of local forcesand governments. Much of the campaign against such groupswill involve fnancial, intelligence, diplomatic, and informationalinstruments. But the U.S. armed forces play crucial roles in train- ing, advising, and assisting partner governments in counteringterrorists and in conducting direct attacks, when appropriate. U.S.special operations forces play a leading role here, but they oftenrequire transportation, logistics, and other types of support fromthe general-purpose forces. Finally, U.S. forces are called upon to protect the United Statesitself from attack. Under normal circumstances, this means keep- ing the national missile defense system and elements of the strategicnuclear forces on alert, being prepared to intercept airborne threatsfrom hostile powers or terrorists, and assisting the Department ofHomeland Security in monitoring the nation’s borders. Tis is a very demanding set of missions. Fighting and win- ning major wars on the territory of distant countries or in their“backyards” is particularly daunting, but this is what the bulk ofAmerica’s armed forces have been trained and equipped to do sinceWorld War II. At present and for the foreseeable future,the UnitedStates alone has the military wherewithal to project large-scale militaryforces over intercontinental distances and conduct sustained militaryoperations across a broad range of mission sets . Tis capability isessential in order to ofset major imbalances in military power andto sustain the United States’ role as the security partner of choicefor like-minded states. Without it, the credibility of the U.S. deter- rent and of U.S. alliance commitments would erode, as would U.S.power and infuence. Unfavorable Trends In the post–Cold War period, the ability of U.S. forces, in conjunc- tion with allies, to defeat aggression by the forces of its regionaladversaries—states such as Iraq, Serbia, and Libya—was unques- tioned. U.S. and allied forces repeatedly demonstrated that, inconficts against these adversaries, they could quickly seize theinitiative; dominate military operations in the air, at sea, on land,in space, and in cyberspace; and achieve their campaign objectivesswiftly. Tis military dominance yielded strategic benefts, not onlyhelping to deter challenges to the U.S.-led global order, but alsoserving as the “glue” that held together coalitions of like-mindedAt present and for the foreseeable future,the United States alone has the militarywherewithal to project large-scale militaryforces over intercontinental distances andconduct sustained military operations acrossa broad range of mission sets. 4 states that promoted common action on a wide range of interna- tional issues. Unfortunately, the era of unquestioned U.S. military superior- ity has not persisted. A variety of factors are responsible for this.First, the vision profered by the United States and other demo- cratically governed states of societies run according to pluralisticnorms and free market economies has not (yet) proven sufcientlycompelling to prompt signifcant and lasting change in many coun- tries. Authoritarian elites in Russia, China, North Korea, Iran, andother states see it as being in their interest to fan historically basedanimosities toward neighboring states and groups and to challengeelements of the U.S.-led international and regional orders.7 In sup- port of these strategies of opposition, the military establishments ofthese states have closely studied U.S. power projection operationssince Operation Desert Storm (ODS), with an eye toward fnd- ing ways to thwart potential U.S. military interventions in theirregions. To varying degrees, their eforts have borne fruit (as will bediscussed later). At the same time, the United States and many of its closest allieshave, since 2001, invested considerable human and material resourcesin eforts to stabilize the situations in Afghanistan and Iraq and tocounter violent extremist groups elsewhere that are deemed to posethreats to citizens of the United States and of its allies. Te ensuingoperations have been a drain on attention, money, and patience ata time when economic constraints have limited defense spending.Training