THE HALLMARK of the Donald Trump administration’s National Security Strategy (NSS), which was released in December, is the idea of “principled realism.” This marks a decided shift from the policies of Trump’s two immediate predecessors. President Bush, with his expansive freedom agenda, set a high priority on the use of U.S. power to promote liberty and democracy. President Obama, less committed to the idea of American exceptionalism and more doubtful of the value of the American role in the world, sought to disengage and “lead from behind.” The Trump NSS, by contrast, represents a return to realism.

In his valuable book Realpolitik: A History, the British historian John Bew explains that realpolitik, or realism, was not, as often characterized today, an amoral approach to foreign policy. Instead, it arose in the nineteenth century in Germany, where figures such as Ludwig von Rochau, who believed in classical liberalism and who participated in the 1848 revolution, struggled to define a foreign policy that was true to their ideals but also cognizant of the limits of their power vis-à-vis states and empires ruled by authoritarians. As Bew puts it, realists focused on the question of “how to achieve liberal enlightened goals—which included balance and equilibrium—in a world that did not follow liberal enlightened rules.”

How has the Trump administration sought to resolve this dilemma? First, it has avoided the trap of equating strategy with a wish list of goals, disconnected from the realities and limits of power.

In the past, the NSS document has often consisted of bottom-up aggregations of policies, which were essentially just stapled together and labeled a strategy, but did not comprise actual conceptual frameworks or orderings of priorities. The administration deserves credit for undertaking this strategy process early on.

In fact, the new NSS is the first serious top-down, government-wide strategy produced since the well-known Defense Policy Guidance (DPG) produced by the Pentagon in 1992, after the end of the Cold War. While the DPG—which I played a key role in formulating—was not embraced as a national-security strategy by the George H. W. Bush administration, many of its concepts shaped subsequent strategy documents and policies.

Second, the Trump administration took a clear-eyed look at world politics and at how we are currently positioned. In 1992, we had arrived at a unipolar moment at the end of the Cold War. The United States was preeminent, and the issue was how to consolidate that preeminence, preclude the rise of a global rival and prevent the domination of critical regions by hostile powers. That brief unipolar era is over.

Today, in critical regions, the mission of interstate competition has returned. China, Russia and Iran now present competitive challenges to the United States and its allies and partners. Beijing, by virtue of its dynamic economy, military buildup and assertive maritime claims, is the primary strategic competitor. Russia seeks to dominate its periphery. North Korea not only seeks coercive leverage over South Korea and Japan, but also is on the verge of being able to threaten American population centers with nuclear weapons. Also, regional and global trends have made many regions unstable, producing streams of refugees that in turn have had major political impacts. Threats from nonstate actors such as international terrorists, at times sponsored by hostile states, have grown.

Third, implicitly and sometimes explicitly, the new NSS identifies strategic errors by which the United States has contributed to today’s challenges. At times the United States has recklessly disengaged, while at other times it has rushed forward with inadequately thought-through plans, or failed to take advantage of the golden hour presented by its actions. In still other instances, the United States has failed to preclude emerging threats in a timely manner. Often, it naively believed that the political systems of adversaries would converge with American values, or that generous arms-control or trade deals would induce other countries to follow the U.S.-led international order. These mistakes crossed party lines and involved both the executive and legislative branches. As a result, the balance of power in key regions shifted toward adversarial powers.

Fourth, the Trump administration has struck a new, cogent position in the perpetual debate about whether the United States’ foreign policy should be guided by the national interest or the country’s values and ideals. The Trump doctrine, reflective of a nation that is questioning the wisdom of some recent international ventures, suggests that the balance has shifted in favor of interests.

As a member of the board of the National Endowment for Democracy, I was forcibly struck by the document’s demotion of democracy promotion. Unsurprisingly, given the president’s views of the wars in Iraq and Libya, regime change is out for now. Challenging authoritarian regimes about their treatment of their own people also seems to command less importance, though the president has spoken forcefully about the situations in Venezuela and Iran.

However, the document does tout the need to provide the world with an inspirational example and collaborate with like-minded aspiring states. Trump’s approach is to enhance America’s success—and hence its example—while respecting other states’ sovereignty to chart their own political destinies. He will speak to the aspirations of others to achieve freedom—thereby standing for American principles—but acknowledge that the United States cannot right all the world’s wrongs. This is the heart of “principled realism.” It means a policy of advancing values, but with greater prudence.

THE UNDERLYING logic of the Trump administration’s diagnosis of the competitive nature of world politics and recent negative shifts in regional balances of power leads to a set of appropriately ambitious lines of action.

The first focuses on the centrality of improving the underpinnings of U.S. power, especially the country’s economic performance. This is key, as the United States cannot sustain its relative power position in the world if the foundations of its power atrophy.

On the economic front, the United States faces the fiscal challenge of supporting entitlements, social programs, and defense and international-affairs spending, at a time when the national debt and annual deficits are already at historically high levels. We will not be able to manage this challenge without higher rates of economic growth. Whether it will be possible to reach and sustain 3 or 4 percent growth—the president’s goal—remains to be seen. However, if we stay at 2 percent or less, the United States will likely be forced to choose between domestic social programs and the United States’ world role, which is not a desirable choice to face. The focus of the NSS on the U.S. economy is sound.

In terms of defense, the document rightly calls for restoring U.S. military overmatch against potential adversaries, to achieve “peace through strength.” National Security Adviser H. R. McMaster is often quoted as saying that, since the end of the Cold War, any time the United States entered a military conflict it was not a fair fight, and that preserving this overmatch must be a key security goal. This preeminence is eroding and needs to be restored. To do so, we will have to spend more, and use those resources wisely.

The vital importance of military balances is something Americans like to wish away. The 1992 DPG called for the United States to maintain a military capability that would discourage the rise of a peer competitor. Unfortunately, post–Cold War administrations cut U.S. capabilities by too much, opening the door for rising powers to pursue favorable balances of power at the regional level. At the same time, the diffusion of military technologies, particularly those of the precision-guidance revolution, means that America’s rivals are leveling the playing field. The U.S. response has been to whistle past the graveyard, defining down defense requirements and then capping this shortsightedness with the Obama-era sequestration that has badly undermined readiness and modernization.

The new National Defense Strategy, which appropriately derives from the NSS, provides a bracing description of the need to reset and bolster U.S. forces for a complex environment that involves the return of great-power competition, the need to deter and counter rogue regimes, and the imperative of continuing the fight against transnational terrorists. Every domain is now contested, and the homeland is not a sanctuary.

The unclassified version of the strategy does not describe the administration’s force-sizing criteria in detail. However, it states that in peacetime U.S. forces must be able to deter aggression in three key regions—Europe, the Indo-Pacific and the Middle East—as well as degrade terrorist and WMD threats and compete below the threshold of war. In wartime, the strategy states, the fully mobilized force must be capable of “defeating aggression by a major power; deterring opportunistic aggression elsewhere; and disrupting imminent terrorist and WMD threats.” In peace and war, U.S. forces must maintain strategic deterrence and homeland defense.

The unclassified version also fails to provide detailed descriptions of the new operational concepts or technologies that will be needed, but it makes clear that Defense Secretary James Mattis intends to shape up the Joint Force for a new era. The emphasis is on increasing the lethality of the force, though the United States will also have to come to terms with shortfalls in capacity and numbers. Mattis has highlighted the need to reform the Defense Department and specified what he expects from reform.

Based on these documents, the administration has a lot of work to do. Trump has made a down payment on improving readiness, but the defense budget must be raised further to overcome reckless past decisions. It will take perhaps a decade to repair the damage.

The second line of action is to shift key balances of power in favorable directions. Like the 1992 DPG, the Trump administration’s NSS recognizes that the important contests lie at the regional level—which, if not managed, can lead to global rivalry. China is seeking to be a regional hegemon. Once it achieves this goal, it will seek to become the world’s preeminent power, creating a new bipolar system. Russia wishes to restore its dominance in the territory of the former Soviet Union. Iran aspires to control the Gulf and project power to the Mediterranean. North Korea seeks unification of the peninsula on its terms.

The National Security Strategy is refreshingly blunt on some regional issues that have been soft-pedaled in the past. For example, it clearly calls out the destabilizing role that Pakistan has played in prolonging and complicating the Afghanistan conflict, by protecting, arming and supporting the Taliban and other insurgents. Previous administrations allowed the Pakistani military to play a double game, receiving America’s aid while undercutting its efforts. This document should put them on notice that America knows what they are doing and is not willing to let it continue.

The NSS sets forth realistic courses of action. It advances a sensible formula for relations with other great powers: counter disruptive actions, deter conflict and cooperate in areas of common interest. This recognizes that the purposes and goals of China and Russia are at odds with America’s own, but it also acknowledges that it is better to avoid conflict, and that all parties’ interests are aligned on some important issues.

A sophisticated policy toward an adversarial power ought always to involve a mix of engagement and containment, or what I previously have termed “congagement.” The document rightly recognizes that the containment element requires restoring the hard-power balance of forces and to compete actively against adversarial powers, while also noting the possibility that engagement can yield important benefits. Yet, taken as a whole, the NSS clearly suggests that the emphasis needs to shift toward containment.

It is gratifying, in light of his campaign rhetoric, that the president now embraces America’s alliances and partnerships. Previously, he had given the impression that these relationships had little—or even negative—value. The NSS highlights the importance of alliances to the balance of power. The aggregate GDP of the United States and its allies exceeds 50 percent of the world economy, and the alliances enable U.S. forward presence. Conceptualizing the Indo-Pacific as a geopolitical entity and strengthening ties with a rising India are smart policies.

At the same time, President Trump—correctly—calls on America’s partners to carry an equitable share of the burden of common defense. As adversaries increase their capabilities, maintaining the balance of power cannot be done by the United States alone. Although he has been criticized for demanding more from U.S. allies, the thrust of President Trump’s approach is on the mark. Realistically, without greater effort by America’s allies, it is hard to imagine the American people remaining committed to the United States’ role in the world.

A third—and distinctive—line of action is the competition in the new domain of data and information. These new tools can affect competition through cyber offense and defense embedded in wider military operations. They shape economic competitiveness through theft of intellectual property and relative performance of firms by improving their productivity and efficiency. They have brought entirely new concerns and potential deformations to political contests through, for example, the weighting of messages in social media. There is also competition over who sets the rules that govern the structures and operations of the internet. The document’s identification of the importance of this issue accurately recognizes the new challenge before us.

The fourth line of action is the competition of ideas. As a country, we need an informed discussion about the means and limits of ideological influence and democracy expansion. We certainly don’t want to abandon those goals, but it is important to do a lessons-learned analysis from our experiences, including whether we have been appropriately organized to carry out democracy promotion in the broader Middle East.

While abandoning the effort altogether would not be right, simply heralding the American example might not be enough. It should be recalled that our greatest adversaries have been ideological foes, and their greatest weaknesses lay in the denial of the human quest for freedom. Our greatest geopolitical triumphs have typically involved the transition of formerly authoritarian or totalitarian powers to more democratic forms of government. We have a strong hand in this domain. To play it poorly would leave potential winnings on the table.

The strategy’s final line of action points to the need for institutional change. From my personal experience as an ambassador in conflict zones, I can testify that our departments and agencies are not as well structured, staffed and integrated as they should be to succeed in the missions we assign them. The strategy document repeatedly emphasizes the need to renew and reform our policy instruments. It highlights the need for a more competitive diplomacy to advocate for U.S. interests.

WITH THESE advantages, the bad news for the Trump administration is that the hard part still lies ahead. A strategy is just a piece of paper until it is operationalized in policies, funded in the budget and implemented on the ground. Reforming departments and agencies is even more challenging. In recent years, the United States’ record in this part of the process has been spotty.

While the Trump administration has set its course in some areas, such as the strategy for Central and South Asia, it is unclear how the strategy will be operationalized in other areas. With respect to China, the administration has made clear its intention to build up a U.S. naval presence, but has not articulated an operational concept. It should work with Japan and other partners to establish a strong line of defense at the first island chain, running from the main islands of Japan through the Ryukyus, Taiwan and the Philippines. It should maintain the ability to project power into the East China Sea. In the South China Sea, it must develop an approach to negate the advantages that China has sought through the creation of bases on a set of strategically located man-made islands. In the wider Indo-Pacific—a helpful geographic concept—the goal should be strengthening alliances and partnerships into a networked security architecture. This would be less than a formal alliance, but would entail a useful alignment of states.

At the same time, President Trump should roll out a campaign of action to create an equitable trade relationship and prevent China from using economic ties to bolster itself in the military realm. Even as it works to establish this position of strength, the United States should seek to work with China on the North Korean question.

When it comes to Europe, the Trump administration emphasizes the centrality of the NATO alliance in dealing with the Russian threat, instability from the south and terrorism. NATO faces two issues regarding the balance of power. The first is the conflict in Ukraine, where the United States has made the first steps toward abandoning Obama’s policy of withholding lethal military assistance from Kiev. The pace and extent of the effort to arm Ukraine should be guided by the goal of defeating Russian aggression in eastern Ukraine and setting a balance that can lead to productive negotiations. The second issue is the need to restore NATO’s deterrent capability against modernized and highly capable Russian forces. The United States needs to lead an effort to work out a division of labor and investment within the alliance that will develop the capacity to deter and, if necessary, defeat a Russian action against the Baltic states. Most of the effort should come from the Europeans, with the United States playing a reinforcing role. This will require determined diplomacy and creative military thinking.

In the Middle East, the United States requires a more comprehensive strategy to check Iran’s quest for hegemony. President Trump has indicated his dissatisfaction with the Iran nuclear deal, but he has not set forth a competitive strategy for the region as a whole. In light of the unrest in Iran, there may be a moment of opportunity. In Iraq, we should work with leaders of all communities to diminish Iran’s influence. In Syria, the United States should continue supporting partners such as Turkey and Jordan, as well as local Syrian proxies, to consolidate success after the defeat of the Islamic State. In doing so, America should create a blocking position against Iran in eastern Syria, as well as a buffer zone along the borders with Jordan and Israel. This would obstruct Iran’s strategic aim of establishing a land corridor to the Mediterranean.

In terms of institutional reform, the agenda is long. For the State Department, the greatest need is not reorganization but cultural change. While the Foreign Service is talented at traditional diplomacy—reporting and delivering talking points—it needs to become more mission driven and expeditionary. Younger officers deployed to Afghanistan and Iraq represent a unique opportunity. They know it’s not enough to “watch and report”—and they are motivated to deliver a political outcome. The Trump administration, which has been tragically slow in staffing the State Department, needs to restructure the recruitment, training and incentive system for diplomats, in order to develop a Foreign Service that can operationalize—and lead—the strategy it has set forth.

I have long thought that USAID should be split in two. The sections that, quite capably, provide disaster and humanitarian relief should be retained as an independent organization. The rest of the agency should be folded into the State Department. Programs that support democratization and better governance should be run by political officers, while economic assistance should be controlled by embassy economic sections. This would not only improve the strategic coherence of foreign-policy programs, but also inject a needed operational ethos into the Foreign Service.

The U.S. capacity to compete ideologically must be rebuilt from the ground up. The country’s international broadcasting system—which was one of its strongest assets in the Cold War—has lost its way. It has had poor leadership and lacked a clear mission. Also, in relying principally on shortwave radio, it is outdated in the age of the Internet and social media. Washington is being beaten by Russia Today, Al Jazeera and China’s growing media presence.

A great deal of work lies ahead on military modernization. The coming Nuclear Posture Review will set the course for a decade-long and much-needed modernization of America’s strategic weapons and platforms, most of which date from the Cold War. The Army lacks a modernization program worthy of the name. It will have to design a force structure capable of operating simultaneously against peer competitors (such as Russia) and irregular opponents. The Navy faces a future in which precision-guided missiles and counterspace capabilities will pose an increasing threat to the U.S. capacity to project power into the littorals of Eurasia. It has not yet come to terms with that challenge in the design of its future forces. And the Air Force continues to be biased toward short-range, manned fighter aircraft, even as adversaries and technological trends reduce the value of such systems. The good news is that the National Defense Strategy indicates that a comprehensive rethink is on the administration’s agenda.

In the cyber domain, the United States has the greatest capabilities—but also the greatest vulnerabilities. A priority should be developing an approach to secure the critical parts of the .gov and .com worlds to the same extent to which we have secured the .mil domain. Securing the key elements and control systems of the electric grid should be at the very top of the list. This will require new legislation, regulation and innovation, and it is unlikely to take place unless driven from the White House.

The Trump administration’s NSS is the vital first step in setting a strategic course. The National Security Strategy gives us a baseline to judge the administration’s performance going forward. Let us hope that the administration will deliver, as the president likes to say, ahead of schedule and under budget.

Zalmay Khalilzad, a former director of policy planning in the Department of Defense, was the U.S. ambassador to Afghanistan, Iraq and the United Nations. He is the author of a new book, The Envoy: From Kabul to the White House, My Journey Through a Turbulent World, from St. Martin’s Press.

Image: U.S. National Security Adviser H.R. McMaster (standing) speaks with U.S. President Donald Trump as he meets with China's Premier Li Keqiang (C, in background) at the Great Hall of the People in Beijing, China, November 9, 2017. REUTERS/Jonathan Ernst