Opinion The America trap: Why our enemies often underestimate us

Editor at large
January 19, 2023 at 9:21 a.m. EST
(Eleanor Shakespeare for The Washington Post)
39 min

Editor’s note: The brief, unsettling moment in history between the end of World War I in 1918 and the United States’ entrance into World War II in late 1941 covers the same timespan as between 2000 and today: 23 years. America in that earlier interval moved from war footing to almost total isolation and then to fighting in an even more deadly conflict.

The United States’ instincts in the 1920s and 1930s, as historian and Opinions editor at large Robert Kagan reminds us, were decidedly insular. Americans saw their nation as a world power but balked at the responsibilities that came with it. That would prove hard to change.

In an exclusive adaptation from his new book, “The Ghost at the Feast: America and the Collapse of World Order, 1900-1941,” Kagan details the global rise of fascism beginning in 1925, tallies the miscalculations of Berlin and Tokyo as both pondered what they imagined to be a neutral United States, and reminds us that President Franklin D. Roosevelt built domestic support for intervention slowly — maybe too slowly — because he did not want to get ahead of the public.

In circumstances that may speak to the present, the combination of events created what Kagan calls “the America trap” — the tendency of our enemies and rivals to underestimate what the United States can accomplish when united.

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How quickly do times of apparent peace become times of conflict; seemingly stable world orders come crashing down; the hopes of many for improvement of the human condition are dashed and replaced by fear and despair.

For the first dozen years after World War I, the three powerful democracies — the United States, Britain and France — were in substantial control of world affairs, economically, politically and militarily. They established the terms of the peace settlement, redrew the borders of Europe, summoned new nations into being, distributed pieces of defunct empires, erected security arrangements, determined who owed what to whom, and how and when debts should be paid. They called together the conferences that determined the levels of armaments the major nations could possess.

All this was possible because they had won the war; because the United States and Britain controlled the banks and the seas; because France wielded predominant military power on the European continent. With this power, the three Western democracies sought to establish and consolidate a world system favorable to their interests and preferences. They argued over how best to do this, and they became increasingly estranged from each other in these years. But they all wanted a stable, prosperous and peaceful Europe. They all sought to preserve their global empires, or, in the United States’ case, its hemispheric hegemony. They all sought to defend the liberal, capitalist economic system that enriched and protected them and in which they believed. None doubted the rightness of their vision of international order or much questioned the justice of imposing it.

And there had been successes, certainly from their point of view. By the second half of the 1920s, the world had grown less violent and marginally less miserable. In Europe especially, economies were recovering, living standards were rising, general violence was down from the immediate postwar years, and the dangers of war and aggression seemed as low as they had been in decades. Internationally, trade had risen by more than 20 percent, despite growing protectionism, driven largely by the American economic boom. Nations spent more time discussing measures for peace than preparing for war. The League of Nations had come into its own. Germany seemed to be on a moderate, democratic course. In general, the threat of a return to autocracy and militarism seemed low. Democracy seemed to be ascendant.

The fascist challenge­­­

Even those who openly defied the new order had to move cautiously. The Soviets promoted their revolution abroad but not so aggressively as to challenge the dominant powers, and they wound up settling for “socialism in one country.” Benito Mussolini, ruling an Italy surrounded in the Mediterranean by British and French naval power and dependent on the United States for financial support, thought it best to play the responsible European statesman. The 1920s were his “decade of good behavior.”

Adolf Hitler, too, proceeded with caution as he ascended to power in the early ’30s. Impressed by the United States as “a giant state with unimaginable productive capacities” and by Anglo-American domination of the global economy, and well aware of the role it had played in selecting Germany’s past governments, he worked at first to soften Washington’s opposition to his rise. He reached out to the U.S. ambassador, gave numerous interviews to prominent American media figures, including William Randolph Hearst, in the hope of making “the personality of Adolf Hitler more accessible to the American people.” He promised to pay Germany’s “private debts” to American bankers and went out of his way to assure the English-speaking world that his national socialist movement would gain power only in a “purely legal way” in accordance with the “present constitution.” After taking power, he told the press and his own officials to play down the campaigns of antisemitism that began immediately. He sought to keep German rearmament under wraps in what he called the “perilous interval” during which the “whole world” was “against us.” Until the economy recovered and German rearmament was further along, he feared that the national socialist revolution could be crushed at any time by the superior power of the democracies.

It was remarkable how quickly the winds were shifting, though. An American journalist identified the moment when history pivoted. “In the first five years after the World War,” he wrote, “the nations of Europe, on their backs and seeking American aid, took all pains to avoid offending us and therefore appeared to give careful and weighty consideration to our altruistic advice. The succeeding five years have changed that.”

One indicator of the shifting trends was the declining fortunes of democracy throughout Europe. It was inevitable that some of the new democracies, implanted in lands that had never known such a form of government, would not survive. The rise of dictatorship in various forms in Hungary (1920), Italy (1925), Lithuania, Poland and Portugal (1926), Yugoslavia (1929), Romania (1930), Germany and Austria (1933), Bulgaria and Latvia (1934), and Greece (1935) had many internal and external causes, including the global depression that began around 1930. But the overall decline of European democracy from the second half of the 1920s onward, and the turn away from democracy in Japan, also reflected the declining influence and appeal of the great-power democracies and their order.

Liberal democracy was not just losing ground. It faced a potent challenge from a vibrant and revolutionary anti-liberal doctrine that attracted followers and imitators throughout Europe and beyond. Americans, British and French during World War I and for decades afterward assumed that Bolshevism posed the greatest threat to liberal democracy. But Bolshevism proved less easily exported than both its proponents and its opponents believed. Ostracized by the rest of Europe, the Soviet Union turned inward to wrestle with the transformation of its society. When democracies fell in the 1920s and ’30s, they fell to the Right, not the Left.

Mussolini’s fascism had many roots. Some of the fascist worldview was unique to the Italian experience, but some of it transcended national boundaries. Above all, fascism represented a rejection of liberalism and the postwar Anglo-American political and economic order that had been imposed on the peoples of the “have-not” nations. Fascism promised to restore national and ethnic identity and culture even while modernizing the nation to compete in an industrializing world. It glorified the people not as individuals but as a collective, with the nation serving as the vehicle for their common destiny. Individual rights and legal processes had to be subordinated to the popular will, a will that could only be understood, articulated and executed by a single charismatic national leader, Il Duce, in whom the people could place their trust. By 1925, Mussolini introduced the idea of the “totalitarian” society, in which the state oversaw every aspect of life or, as he put it, “everything within the state, nothing outside the state.”

Fascism was not an ideology of peace. To revise or overthrow this unjust order would require military power and the will to use it. “Words are beautiful things,” Mussolini said, “but rifles, machine guns, ships, aircraft, and cannon are still more beautiful.” Society had to be purged of flabby liberalism, quarreling political parties and alien elements, and forged into one unified collective fit for war. The people needed to be prepared for war by rigid control of politics, economics and society, and the elimination of all institutions that could stand in the way of the leader’s total power, from the church to the aristocracy to the remnants of monarchy. Hitler’s entire program was aimed at creating a new Germany that would not fail as Imperial Germany had in 1918. Democracy was “the most disastrous thing there is,” he told his top generals on the eve of taking power. “Only one person can and should give orders.” The German population had to learn to “think nationalistically and thus be welded together,” and this could only be accomplished by force.

This fervent nationalism had transnational appeal. “Whoever says that fascism is not an exportable commodity is mistaken,” Mussolini declared. He hoped and expected that it would become to the 20th century what liberalism had been to the 19th. He even tried to promote fascism in the United States. He saw himself as “the Pope of antidemocracy” leading an “antidemocratic crusade throughout the entire world.” In the 1920s and ’30s, fascist movements of varying hues and size cropped up in practically every nation in the world. It made less headway in Britain and the United States, where democracy was more firmly rooted, but it thrived in countries where liberal democratic institutions were new and fragile, including in France. Where fascism did not succeed, as in Romania and Hungary, it was usually because the government was already sufficiently right-wing and nationalist that fascists could not find an opening. Even in China, Chiang Kai-shek and his advisers marveled at how Mussolini had become “the greatest and most picturesque statesman in Europe” and thought that fascist Italy offered a model for how China could restore its national strength “through the revitalization of a past great civilization.”

Mussolini always had international ambitions, even if in the 1920s he lacked the means of pursuing them. He was encouraged by the Japanese aggression in Manchuria and the weak and faltering response of the League of Nations and the United States. When Japan announced its withdrawal from the League of Nations in 1933, it was a sign that the other “have-not” nations might be willing and able to mount a rebellion against the Anglo-American system. But ultimately, it was to Germany that Mussolini looked for salvation. As far back as 1923, he had believed that the “axis of European history passes through Berlin.” He saw in Hitler’s rise to power the historic opportunity for which he had been waiting.

Hitler saw the fascist seizure of power in Italy as “a harbinger of his own success” and had such admiration for Mussolini that when they met for the first time in the summer of 1934, he had tears in his eyes. Mussolini believed a “community of destiny” united the fascist powers. The “alliance between the two nations,” his foreign minister declared, was based above all on the “identity between their political regimes.” By the mid-1930s, the Japanese had joined the anti-liberal club. As Yosuke Matsuoka, a leading Japanese fascist in the 1930s, argued, each of the have-not nations was fighting for “recognition and its place in the eyes of the world.”

The entry of Japan into what Hitler would call the “triangle” of challengers to the Anglo-American system was the final step in a geopolitical revolution. As one Japanese author noted in 1934, the world now contained “two tinderboxes,” one in the western Pacific and one in Europe, and the two were “interlocked.” A crisis in one “can easily extend to the other and assume a global character.” Hitler believed that if the British were confronted not only by Germany and Italy in Europe but also by “a common organized force in the Far East,” they would have no choice but to accept Germany’s rise and even seek “common ground with this new political system.”

Accelerating toward war

President Franklin D. Roosevelt was an internationalist, but he spent his first term in office fighting the Great Depression and his second term trying to cajole Americans out of their rigid anti-interventionism. After the fall of France in 1940, he shifted into a more alarmist mode. The conquest of France gave the Germans new bases on the Atlantic coast from which to operate against British shipping and their naval convoys. This greatly extended the reach of the German U-boat fleet, which had grown more sophisticated in its tactics. The Germans by early 1941 were sinking British merchant ships at a rate more than five times Britain’s capacity to replace them. Roosevelt’s alarmed advisers argued for direct American military involvement to protect Britain’s transatlantic lifeline. Roosevelt, who feared that the public was not yet ready, was reluctant to take such a big “step forward” — to which Secretary of War Henry L. Stimson replied, “Well, I hope you will keep on walking, Mr. President. Keep on walking.”

Roosevelt did. He began allowing British ships to be repaired in American ports. He transferred Coast Guard cutters to the Royal Navy. He gained the Danish government’s permission to place Greenland under American control and authorized the establishment of bases there to help defend transatlantic shipping. In April, he authorized the Navy to begin working with the British on plans for escorting convoys. And although he continued to shy away from announcing such a policy openly — an April poll suggested the public was still opposed, 50-41 percent — he ordered U.S. naval patrols to help the British spot German subs.

A string of Nazi victories in the spring of 1941 made the situation more dire. German forces invaded and occupied Greece; Yugoslavia fell in 11 days. With Gen. Erwin Rommel leading his Afrika Korps, the Germans were punishing British and Australian forces in North Africa. British Prime Minister Winston Churchill begged Roosevelt to step up American assistance and even to enter the war officially. Unless the United States took “more advanced positions now, or very soon,” Churchill warned, “vast balances may be tilted heavily to our disadvantage.”

Roosevelt agreed that the situation was grave and pushed ahead as far as he thought the American public would allow. “Unless the advance of Hitlerism is forcibly checked now,” he warned in a speech at the end of May, “the Western Hemisphere will be within range of the Nazi weapons of destruction.” He issued a proclamation that “an unlimited national emergency exists” and called for “strengthening of our defense to the extreme limit of our national power and authority.” In June, he ordered 4,000 U.S. Marines to take positions in Iceland, allowing British forces there to operate elsewhere. As Lord Halifax, Britain’s ambassador to Washington, observed, Roosevelt’s “perpetual problem was to steer a course between … (1) the wish of 70 percent of Americans to keep out of war; (2) the wish of 70 percent of Americans to do everything to break Hitler, even if it means war.”

On Sept. 4, 1941, a German submarine fired torpedoes at an American destroyer, the USS Greer, which in turn dropped depth charges. Even American officials believed the U-boat commander did not know he was firing at an American warship, but Roosevelt made the most of the incident. “This was no mere episode in a struggle between two nations,” he declared in a radio talk. It was part of a determined effort by Germany to create “a permanent world system based on force, on terror and on murder.” American security, he insisted, was now directly threatened. “For if the world outside of the Americas falls under Axis domination, the shipbuilding facilities which the Axis powers would then possess in all of Europe, in the British Isles and in the Far East would be much greater than all the shipbuilding facilities and potentialities of all of the Americas — not only greater, but two or three times greater — enough to win.” Roosevelt warned again that it was “time for all Americans … to stop being deluded by the romantic notion that the Americas can go on living happily and peacefully in a Nazi-dominated world.”

He then announced his new policy. “We have sought no shooting war with Hitler,” he told Americans, and “we do not seek it now.” But “when you see a rattlesnake poised to strike, you do not wait until he has struck before you crush him.” The “Nazi submarines” were “the rattlesnakes of the Atlantic,” he declared. Therefore, “our patrolling vessels and planes will protect all merchant ships — not only American ships but ships of any flag — engaged in commerce in our defensive waters. … Let this warning be clear. From now on, if German or Italian vessels of war enter the waters, the protection of which is necessary for American defense, they do so at their own peril.”

Roosevelt would later be accused of misleading Americans about the risks he was taking. In this case, however, he said he had “no illusions about the gravity of this step. I have not taken it hurriedly or lightly. It is the result of months and months of constant thought and anxiety and prayer. In the protection of your Nation and mine it cannot be avoided.”

As Roosevelt no doubt hoped and expected, the majority of Americans were with him on this latest escalation. Sixty-two percent of those polled approved of a policy of “shoot on sight.” As he also may have feared, however, Congress was less supportive. In an effort to bring the neutrality legislation in line with his new policies, Roosevelt first asked Congress to revise the legislation to allow American-flagged merchant ships to arm themselves for the transatlantic crossing. He then asked Congress for a further revision allowing American vessels to deliver Lend-Lease goods directly to British ports, instead of having the British pick them up at U.S. ports. This passed the Senate, but only by 50-37, the smallest majority of any foreign policy vote taken since the outbreak of the European war. In the House, revision passed by only 18 votes, 212-194, despite the Democrats’ 268-162 majority. It was clear to Roosevelt that it would take more time and more severe “incidents” to bring the country around.

If Roosevelt was waiting for Hitler to fire the first shot, however, he would have to wait a long time. From giving almost no thought to the United States as a factor in the war, Hitler had since come to regard the Roosevelt-led Americans as a serious obstacle. By late 1940, all his strategic plans revolved around keeping the United States out of the war until he was ready to take it on.

Roosevelt’s reelection to a third term in November 1940 made the United States’ eventual involvement almost a certainty. In December, German intelligence noted that interventionist sentiment seemed to be growing, thanks largely to Roosevelt. Hitler and his advisers knew that in 1941 U.S. aircraft production would exceed that of the Reich and that by the end of 1941 the United States would possess a modern, well-equipped army with 1.5 million troops. Hitler told Gen. Alfred Jodl in December 1940 that Germany needed to solve all continental problems in 1941 “because in 1942 the United States will be ready to intervene.”

German officials had long regarded Japan as a critical asset when it came to the United States. The Germans assumed that the United States would do anything to avoid a two-front war — always the Germans’ own nightmare — and that fear of Japan would force Roosevelt to keep the bulk of the American fleet in the Pacific rather than the Atlantic. In September 1940, Hitler told Mussolini that “a close cooperation with Japan” was the “best way either to keep America entirely out of the picture or to render her entry into the war ineffective.” Whether the Japanese could be induced to play this role, however, was uncertain and would be a continuing source of anxiety for Hitler for the next two years.

Japan’s hostility toward and fear of the United States had certainly grown in recent years. The first critical turning point had come in 1931 with the Japanese conquest of Manchuria. The attack badly damaged relations between Japan and the United States. It also both revealed and strengthened some new trends in Japanese society, particularly the growing influence of the military, and within the military, the growing influence of younger, more aggressive army officers. This was part of a broader shift in Japanese society. After a decade of relatively liberal and democratic government and cooperation with the United States and the West, many Japanese increasingly came to reject the Anglo-American liberal capitalist world order, and, indeed, liberalism itself, as a constraint on Japanese national ambitions. In 1934, the army ministry published a pamphlet denouncing the “ideas of liberalism, individualism, and internationalism which neglect the nation.” It called for “the education of the people in order to organize and control the great potential spiritual and physical energy of the imperial nation for the sake of national defense and to administer it in a unified manner.”

As in Germany, much of the drive for unity and national organization aimed at preparing the people for the great struggle ahead. If saving the Japanese soul, spirit and nation meant throwing off the dominating influences of the Anglo-American order, that could hardly be done while Japan remained dependent on, and therefore vulnerable to, American economic power. Military and civilian leaders insisted, as some of them had been doing for decades, that Japan’s survival required further expansion to acquire the resources necessary to relieve the dangerous dependence.

Some advocates of the “new order” in Asia believed it could be achieved without collision with the United States. Others feared that the United States would never tolerate Japanese expansion and control of China and would eventually seek to thwart it. Therefore, Japan had to move quickly to acquire the resources and power necessary to prevail in the inevitable conflict.

In practical terms, this meant striking out in new directions to end Japan’s dependence on the United States, particularly for that most vital of military resources, oil. The Imperial Navy argued for an expansion of naval power into the South Pacific to gain access to natural resources in advance of any possible conflict with either the United States or the Soviet Union. Only with secure access to the oil reserves of the Dutch East Indies could Japan safeguard what it had already gained in China and prepare for future contingencies. In 1936, the Japanese leadership decided to pursue this southward advance.

Another turning point came in the spring of 1937. A new government came into office, headed by Prince Fumimaro Konoe, the man who two decades earlier had denounced the “Anglo-Saxon peace” and the relegation of Japan to the status of “have-not” nation. As prime minister, Konoe declared that peace could no longer be the sole object of Japanese foreign policy. It was time for Japan to “work out new principles of international peace from our own perspective.” The full-scale invasion of China that Japan launched in July brought into the open the fundamental clash between Japan and the West. After Japanese forces seized Shanghai, Nanjing, Hangzhou, Guangdong and Hankou, Konoe proclaimed the “New Order” on Nov. 3, 1938, just a month after the British and French capitulation at Munich.

The war in China boldly defied the West and accelerated the evolution of Japanese politics toward authoritarianism and militarism. In keeping with the conservative, antidemocratic trend, Konoe’s ministry launched the nation into a full-scale war economy. A national mobilization law gave the government broad powers as Japan poured more than 1 million troops into China over the first year of the war. When the Konoe government resigned in 1939, amid popular frustration with the high cost and indeterminate results of the war, a new government led by a leading right-wing politician and founder of one of the nationalist antidemocratic societies further deepened the role of the state and the organization of society around the war effort. To Western observers, Japan had moved “a long way on the road to totalitarian statehood.”

If Hitler’s aim was to embroil the United States in a conflict with Japan in order to distract it from Europe, Roosevelt’s aim was not to be distracted. Throughout 1938, the State Department studied options for economic sanctions, which would require abrogating the 1911 Treaty of Commerce and Navigation with Japan, but Roosevelt had not been ready to take that step. In 1939, as public and congressional pressures increased, Roosevelt imposed what he called “moral embargoes” on aircraft and air munitions, intended to discourage American companies from selling such items to Japan. But that restriction proved limited. American companies were still allowed to export steel, aluminum, technology and aviation fuel.

The result was an American policy that neither accommodated nor deterred the Japanese. As Interior Secretary Harold L. Ickes put it, dependence on American resources was a “noose” around the Japanese neck. Roosevelt was “unwilling to draw the noose tight” lest he force Tokyo’s hand, but he was willing to “give it a jerk now and then” to remind the Japanese of the possibility of strangulation.

Roosevelt’s ambivalent approach created a dilemma for the Japanese. As Foreign Minister Yosuke Matsuoka put it at a critical meeting of senior officials in the fall of 1940, Japan could seek a return to cooperative relations with the United States and Great Britain. But it could only do so on the Anglo-Saxons’ terms. Any settlement would require giving up many of the gains made over the previous two decades and getting used to living with the American noose around their necks. Or they could try to remove the noose by acquiring the territory and resources that would relieve their dependence on the United States. This was what the Imperial Navy proposed to do with its plan for a southward advance into Indochina and toward the oil supply of the Dutch East Indies. That meant risking war with the United States.

At no time were the Japanese convinced they could win such a war. More than Hitler, they were acutely aware of their own vulnerability to the United States’ superior economic and industrial strength, its seemingly limitless resources, and its large population. War games consistently showed that Japan could score short-term victories owing to their initial military superiority over Anglo-American forces in the region and also to the inadequacy of American bases in the western Pacific. But within two or three years, the United States would develop sufficient military power to roll back Japanese victories and eventually threaten Japan itself. As the brilliant naval commander and tactician Adm. Isoroku Yamamoto put it, “If I am told to fight, regardless of the consequences, I shall run wild for the first six months or a year, but I have utterly no confidence for the second or third years.”

The America trap

The United States’ intervention was at first disastrous. As Yamamoto predicted, the Japanese did “run wild” for the better part of a year. Ten hours after the attack on Pearl Harbor, Japanese forces attacked American bases in the Philippines. They destroyed half of the U.S. Far East Air Force on the ground along with its installations. American and Filipino Army forces were driven back to Bataan, where they fought tenaciously before succumbing to hunger and disease. Gen. Douglas MacArthur was evacuated from the Philippines on March 11, 1942, and the remaining American and Filipino fighters surrendered on April 9. Tens of thousands were captured. Guam fell quickly, as it was almost entirely undefended, just as it had been for more than four decades. Americans suffered more casualties in a shorter span of time than in any conflict in their history other than the Civil War.

Meanwhile, the British were suffering the “greatest disaster” in their entire history. They surrendered Hong Kong in a matter of weeks. Malaya fell in two months, as British and Indian forces were chewed up, British warships sunk, and tens of thousands taken prisoner. By the end of February, the Japanese Imperial Navy had met and destroyed the combined naval forces of the United States, the Dutch and the British. Rangoon and Burma fell on March 8. In less than six months, Japan had conquered a new empire of some 350 million people, three-fourths the size of the British Empire. All told, Japan conquered more territory in a shorter period of time than any nation in history. To win the war would require the United States, practically by itself, to fight its way back across the Pacific and roll back these massive strategic gains one island at a time.

At the same time, the United States began operations against German forces on the other side of the world. Taking the lead from the British, American forces drove the Germans out of North Africa and then began the attack through Italy. It would be two more years of brutal fighting, especially on the eastern front, before the United States led the Allied invasion of Germany that ultimately ended the war in Europe.

The Americans started slowly, just as they had during the First World War, but once the U.S. economy shifted fully into war production, and as the large and healthy population geared itself up for war-fighting, the tide turned, just as it had in 1918. The U.S. Army, which had numbered 188,000 in 1939, swelled to 5.4 million by the end of 1942. At the end of the war, 12 million Americans were under arms, second in number only to the Soviet Union. American weapons production eclipsed all previous efforts. Shipyards produced almost 9,000 “major naval vessels” between 1941 and 1945, nearly 10 times the number produced by Britain in the same period and 16 times the number produced by Japan. In 1943 alone, the United States built 16 aircraft carriers, which more than replaced their early losses. The Japanese, who lost just as many in the early fighting, built none. American industry produced over 300,000 military aircraft during the war, more than Britain, Germany and Japan combined. The United States also produced 90 percent of the Allies’ aviation fuel and, through Lend-Lease, supplied a quarter of all British munitions and over half of all military vehicles used by the Red Army. The Soviets acknowledged then and later that they never could have held out against the German onslaught without American financial and material assistance. “I drink to the American auto industry and the American oil industry,” Stalin remarked with conscious irony in 1943.

Meanwhile, the American economy soared. While every other great power’s economy collapsed under the strain of total war, U.S. GNP more than doubled. Eleven million Americans joined the armed forces, but 6 million more joined the ranks of the civilian workforce. This expansion allowed the American economy to increase military production without greatly limiting production of many non-war-related goods.

The phenomenon of a single power fighting two full-scale wars on land and sea, financing and producing enough military equipment for itself and its allies, while at the same time also raising its people’s standard of living, was so unprecedented that Hitler could be forgiven for not having anticipated it. He admitted to the Japanese ambassador, soon after declaring war, that he did “not know yet” how “one defeats the USA.” He soon came to regard the war with America as “a tragedy, illogical, devoid of fundamental reality.”

Hitler, like everyone else, including Americans, had not fully realized how much the world had changed and how much the United States’ overwhelming power, both existing and potential, could affect the fate of would-be hegemons in Europe and Asia. But his underestimation of American power was reinforced by Americans’ behavior over the previous two decades.

Hitler fell into a trap unwittingly laid by American policymakers, Congress and the public. In the critical years of his rise to power, the consolidation of his rule, Hitler feared and expected the democracies would come after him during what he called that “perilous interval.” When they did not, and he was allowed to pass undisturbed through his time of greatest vulnerability, he grew overconfident. As early as 1935, Hitler and his lieutenants were already “absolutely drunk with power,” convinced that “the whole world” was afraid of them and would not move against them “no matter what” they did. He was emboldened to reoccupy the Rhineland in 1936 and then to move on to fulfill his ambitions in central Europe. When Roosevelt took office, it was already too late to knock Hitler off his course merely with strong words or even sanctions. By the time Roosevelt actually began trying to convince Americans that they would have to become involved in the general international crisis, both Hitler and the Japanese were so far down the road that they could not be deterred by anything short of a genuine threat of war, and perhaps not even by that.

It mattered a great deal that the United States and the democracies did not successfully contain either Germany or Japan in the late ’20s and early ’30s. The simultaneous rise of two aggressive major powers in two core regions of the world was harder to manage than each would have been by itself. Even though the two powers were never truly allied and consistently mistrusted one another, every German success in Europe spurred further Japanese aggression in Asia, and every Japanese victory in Asia strengthened Hitler’s resolve to press forward in Europe. Both assumed that the Allied powers, and especially the United States, would be distracted by the aggressive moves of the other and fearful of a two-front war. Strengthening this assumption was their common belief — in Japan’s case it was more of a wish and prayer — that the Americans would not fight for anything outside the Western Hemisphere.

How were the leaders of Japan and Germany to know that there would come a point at which Americans would completely change their minds and decide that the stakes were worth risking war? Here the America trap was sprung. By the time the United States finally decided to use its power, after almost two decades of deliberate inaction, it was too late for the Japanese to turn back without a catastrophic humiliation. For Hitler, any hope of deterrence ended after 1936, at the latest. As Churchill put it, “When the situation was manageable, it was neglected, and now that it is thoroughly out of hand, we apply too late the remedies which then might have effected a cure.”

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