As President Biden and his team turn their attention to designing a new national security strategy, they will face a formidable task — one never encountered before in American history. For the first time, the biggest threats facing the United States stem not from great power rivals or geopolitical configurations, but from stateless and even nonhuman actors such as viruses and climate change. This reality demands a wholesale rethinking of national security strategy, budgetary priorities and foreign policy.

From the first days of the American republic, U.S. security was endangered by great powers encroaching on U.S. borders or seeking geopolitical dominance in ways that threatened the vitality of the American economy in peacetime or posed an existential threat in wartime. The founders had to grapple with the British, French and Spanish seeking to contain the expanding republic, sow divisions within it and curtail its trade. American presidents from George Washington to John Quincy Adams all struggled mightily to exploit the rivalries among the great powers. They sought to consolidate territorial gains, annex additional lands and insist on America’s “neutral rights” to trade in wartime or peacetime. In 1823, James Monroe and Adams, then his secretary of state, set forth a new doctrine warning European powers not to intervene in the hemisphere. U.S. security required a neighborhood with no great powers around its periphery.

In the early 20th century, President Theodore Roosevelt added a corollary to what had become known as the Monroe Doctrine. He asserted an American right to intervene anywhere in the hemisphere to thwart the influence of newly ambitious European powers such as Germany.

As Nazi Germany and militarist Japan consolidated power in the late 1930s, President Franklin D. Roosevelt came to see a new threat. He grasped that German domination of Europe and Japanese control of much of Asia would enable the Axis powers to integrate the natural resources, industrial power and skilled labor of Eurasia into their war machines. Such a world would give these empires enormous economic influence over distant regions and endanger the fundamental institutional practices and core values of the United States. “The logic of such implications,” said Roosevelt, “would lead us to embark on a course of action which would subject our producers, consumers, and foreign traders, and ultimately the entire nation, to the regimentation of a totalitarian system.”

World War II, then, bequeathed two overriding strategic lessons for the Cold War: the need for overseas bases and military might to avoid another Pearl Harbor and the necessity of preventing any adversary or coalition of adversaries from dominating the Eurasian land mass. Even as international tensions were thawing in the 1980s, President Ronald Reagan and his advisers restated what remained the most fundamental axion of U.S. strategy: “every Administration since World War II has endorsed the concept that the United States, in partnership with its allies, must prevent the Soviet Union from dominating those great concentrations of industrial power and human capacity that are Western Europe and East Asia.”

After the Cold War ended, President George H.W. Bush’s advisers acknowledged that the greatest threat was uncertainty. But they nevertheless defined American security in terms of regional balances: The United States could not allow any potential adversary, such as Iran, to dominate a region of strategic importance.

In the 30 years since, however, the most fundamental threats have morphed and changed, first with the rise of stateless terrorism and now with enemies such as pandemics and climate change. More people are now dying daily of covid-19 than perished at Pearl Harbor or were killed on 9/11; the U.S. death toll from the pandemic is now greater than the number of U.S. service members killed during the Korean, Vietnam, Afghan and Iraqi wars combined. And according to one recent study by former treasury official Larry Summers and Harvard economist David Cutler, the economic toll over the next decade could reach a staggering $16 trillion.

Climate warming may pose an even more existential threat to vital American interests. Even during the Trump administration, a senior analyst for the State Department’s Bureau of Intelligence and Research said, “Absent extensive mitigating factors or events, we see few plausible future scenarios where significant — possibly catastrophic — harm does not arise from the compounded effects of climate change.” Hurricanes and floods, droughts and fires, environmental degradation, increased poverty and fierce global resource competition are just some of the likely potential harms. The “Fourth Annual Climate Assessment” of the U.S. Global Change Research Program concludes that if the United States undertakes only minor adaptations over the next few decades, there will be staggering losses by the end of the century to health, property, labor productivity, infrastructure and the environment amounting to many hundreds of billions of dollars annually.

Biden recognizes the significance of these new threats, promising a laserlike initial focus on covid-19 and appointing experienced officials to combat the effects of global warming. But the big challenge is whether the new administration will be able to integrate these concerns into its basic national security strategy and into the budgetary priorities, foreign policies and institutional processes that flow from it.

The data reveals why. According to the Government Accountability Office, between 1993 and 2014 annual federal funding to address climate-related risks climbed from a meager $3 billion in 1993 to a still paltry $12 billion in 2014, culminating in a total of about $154 billion over approximately 20 years. Similarly, local, state and federal spending on public health totaled less than $100 billion as recently as 2018. And yet, expenditures on defense rose from about $297 billion in 1993 to about $650 billion in 2018. In short, the United States must rearrange its priorities and spend more money on the most dire and most likely threats.

But reexamining these priorities and the strategy undergirding them will run headlong into experts’ claiming that the threat from China today is comparable to the threat posed by the Soviet Union in the early days of the Cold War — and demanding top priority in any national security strategy. This contention, however, overstates the threat. China’s neighbors are not devastated and demoralized from the events of a cataclysmic war as were the countries surrounding the Soviet Union in 1946 and 1947. Nor are Asian countries engulfed in civil wars, endangered by popular communist parties or facing economies paralyzed by a shortage of capital, exchange restrictions and trade barriers, as was the case in Europe following World War II. Today, China is surrounded by a proud and rich Japan, an ambitious and nationalistic India, a revanchist Russia and a wealthy, competitive South Korea.

The United States cannot dismiss China’s nefarious behavior in Hong Kong or Xinjiang, its adventurous actions in the South China Sea or its illegal trade practices. Washington must not permit China to gain regional hegemony over its neighbors nor allow it to establish exclusionary or discriminatory trade blocs. But unlike the early Cold War years, the United States now has an array of strong alliances, military commitments and trade arrangements with key countries in the region, all which can be employed to manage the threat of China or reconfigured to set the rules and norms of a postindustrial economy.

More significantly, traditional U.S. security priorities do not make sense when transnational threats such as climate change and pandemics are so much more certain, more costly and arguably more dangerous than the great-power competition that policymakers are so accustomed to focusing upon. Future Chinese behavior will be contingent on many variables, and the degree of threat Beijing poses will be contingent on many more factors, but there is no doubt that the climate is warming and that germs are spreading and becoming more lethal. And if geopolitical adversaries and ideological foes are now secondary to nontraditional threats, that demands a recalibration of strategic concepts, budgetary priorities and foreign policies.