The National Interest Is What the President Says It Is

Leaders around the world justify their foreign-policy decisions in the name of the “national interest.” Joe Biden and his aides, for example, have used the phrase to defend the administration’s approach to cybersecurity, refugee admissions, the Afghan War, and growing tensions with China. National interest is a serious notion, pregnant with ideas about collective aspirations. It evokes geopolitical goals—such as territorial expansion, military hegemony, and regional harmony—that transcend individual politicians and are pursued over the course of decades or centuries.

This view of national interest is stirring. It is also divorced from reality in most cases. As American voters prepare to elect a new president, they should take note: Although broad perceptions about what is good for a nation do play a role in shaping its foreign policy, its geopolitical strategy—even in a democracy—is determined mainly by the personal preferences of its leader.

In my latest book, The Strategists: Churchill, Stalin, Roosevelt, Mussolini, and Hitler—How War Made Them, and How They Made War, I examine the control that five national leaders exerted over their country during World War II. One theory of international relations holds that plans developed by established government institutions limit a leader’s prerogatives and are principally responsible for a country’s approach to foreign affairs even in wartime. Yet Hitler and Stalin crushed opposition within their governments, forging ahead with their own strategies. Bureaucratic checks meant to limit power were rendered ineffective in the democratic powers as well: Franklin D. Roosevelt and Winston Churchill outmaneuvered political rivals and military officials who disagreed with their views. Individual leaders’ choices, not policy proposals carefully debated in government departments, were the main factor affecting the fate of hundreds of millions of people and the outcome of the war.

Years before the 1941 attack on Pearl Harbor, as the potential for simultaneous conflicts across the Atlantic and the Pacific was becoming clearer and clearer, the State Department, White House staff, and the military devised a policy that presumed Germany to be the greater threat, and committed to prioritizing its defeat over Japan’s should the U.S. end up at war with both at the same time. Although Roosevelt understood the logic of this approach—and paid lip service to it after Pearl Harbor—he chose not to direct the U.S. toward a Germany-first policy. Instead, under his watch, about half of U.S. military equipment was used to fight the Japanese—an approach that, he believed, would have the benefit of placating voters who wanted the U.S. to make a substantial effort against the country that had attacked Pearl Harbor.

To a striking degree, the way the United States conducted World War II was a consequence of Roosevelt’s own experience as the assistant secretary of the Navy during World War I—a period that made him appreciate the benefits of overwhelming the enemy with machinery, as well as the risks of ground warfare. When he traveled to France in 1918 to tour the front lines, the battlefield disgusted him. The conditions for soldiers were too crowded, and he wrote in his diary that “the smell of dead horses” offended his “sensitive naval” nose. Instead, he fixated on logistics and material: the deployment of large naval guns, transported on land via train carriages, to batter German lines; a push for rapid advances in aircraft and bomb technology. He promoted a plan to thwart German U-boat attacks by creating a minefield across the entire North Sea rather than putting Allied ships at risk. (The scheme was not complete when the war ended.) Roosevelt’s work during this period also showed him the value of working closely with trusted international partners such as Britain and France. Strong alliances, he came to learn, were how modern wars were won.  

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Unlike many Americans, Roosevelt did not become an isolationist after World War I. He understood that aggressive authoritarian regimes had to be stopped and believed that the U.S. could protect many of its own interests via machinery and alliances. He was so wedded to these two ideas that, during World War II, he provided Britain and the Soviet Union with massive amounts of aid without expecting any repayment. So much better, Roosevelt believed, to strengthen U.S. allies and let them do much of the land fighting. This approach led to one of his greatest successes as a war leader. Even though the United States deployed substantially more forces to the Pacific theater than its European allies did, it saw fewer military casualties as a percentage of its population than did each of the other major powers of the war; it suffered 400,000 military deaths, compared with approximately 10 million for the Soviet Union, more than 4 million for Germany, and almost 2 million for Japan.

Roosevelt had less success implementing his goals after the Axis powers’ defeat. He envisioned a postwar world run by what he called the “four policemen”—the U.S., the Soviet Union, Britain, and China—all operating through the United Nations. Yet his approach was fundamentally egocentric; Roosevelt surely had plans for how he would use the new international body to promote peace and protect American interests, but those plans died with him in April 1945, along with any tacit agreements he might have reached with Stalin and Churchill. Roosevelt’s successor, Harry Truman, had little idea what Roosevelt’s policies really were.

A president’s instincts still define much of the United States’ activities abroad. Biden understood the benefits of assisting Ukraine when Russia began preparations to invade. But the president’s fear of nuclear escalation with Russia, along with his misguided confidence in Washington’s ability to micromanage the course of the war, has hampered Ukraine’s ability to maximize the benefits of Western weaponry.

Kamala Harris’s time as a senator and as vice president hasn’t revealed much about whether and how the Democratic nominee’s view of America’s national interests might differ from Biden’s. But she has at least shown a basic willingness to work with formal U.S. allies in NATO and Asia and to support democratic states such as Ukraine that want to be U.S. allies. She’s unlikely to slip into a dangerous and delusional isolation, thinking the U.S. can somehow live in the world without friends.

Her opponent, meanwhile, has defined America’s national interest in terms of his personal whims. Donald Trump seems mostly disdainful of long-standing democratic allies, saying he would be more than happy to leave Europe to “go to hell” and recently criticizing Taiwan as an economic threat to the United States.  

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Trump is an unabashed admirer of dictators, regularly praising North Korea’s Kim Jong Un and China’s Xi Jinping. Trump’s greatest affection is for Russia’s Vladimir Putin, and accordingly, the former president has sought to block U.S. assistance to Ukraine. If Trump regains the White House, he could weaken America’s global position in a way that no president has done before, sacrificing close relationships to curry favor with regimes that are eager to undermine the United States. He and his family might personally make money, via their real-estate holdings and other businesses, from countries that want to influence American policy. Trump is the ultimate example of why there is no such thing as national interest independent of the sentiments of national leaders.

If Trump decides that America’s interests lie in giving in to dictators rather than defending democracy, the bureaucracy won’t constrain him. Ultimately, voters get the policy of the candidate whom they put into power.