On Friday, April 13, 1945, America was petrified. Franklin Roosevelt, the President of the United States, had just died while the Second World War was still not over. Roosevelt was the great architect of peace. More than anyone else, he embodied the hope of rebuilding the world on better foundations.

As the silent crowds watched his funeral procession pass by, the entire planet asked one question: Without Roosevelt, could the Western Allies and the Soviets still get along? Could they build a lasting peace?

April 12, 1945, Washington, at the White House. Three hours after Roosevelt’s death, Harry Truman became the new President of the United States. He stepped into office in a chaotic world. In April 1945, America was still at war—against Hitler and against Japan. And to make things even more complicated, it had only been three months since Truman became Vice President. Nothing had predestined him to truly become the new President of the United States.

He was a former salesman of shirts and ties from Missouri. He had entered politics late and had been elected senator for the first time only ten years earlier. If Roosevelt had chosen him as Vice President, it was not because of his skills. He considered the choice entirely electoral, while privately believing Truman to be useless—a view shared by many throughout the United States.

“When we choose a Vice President, it isn’t necessarily because of his intelligence, but because he’s the one who will bring in votes in the places we need them,” they said.

In a single day, the former Missouri merchant found himself thrust to the head of the world’s leading power. Truman himself was bewildered and did not hide it. On newspaper front pages, journalists reported what Truman confided to them:

“Boys, if you pray, pray for me. I don’t know if a bale of hay has ever fallen on you, but when they told me what happened yesterday, I had the impression that the moon, the stars, and all the planets had fallen on me.”

Truman’s grandson later recalled that his grandfather never tried to pretend he was the right man for the job.

“He said, ‘There must be a million people more qualified than I am to do this job. It fell on me, so I’ll do everything it takes to handle it.’ He was the sort of man who, when given a task, simply did it.”

The mission ahead was daunting. The world of tomorrow had to be rebuilt on solid foundations. Yet Truman had little knowledge of international politics. During the three months of his vice presidency, Roosevelt had met him face-to-face only twice. Truman was aware of nothing.

“I think my grandfather was wrong not to involve him a little more,” said his grandson. “He was fully aware of his declining strength, but I think he didn’t have the energy to bring Truman into his decision-making or to pass the baton properly.”

Two months before his death, Roosevelt had met Stalin and Churchill at Yalta. There, in Crimea, the three laid the groundwork for future peace. The agreements they sealed were complex and full of ambiguities. Each ally played his own game. Truman had been excluded from all of those discussions. He now had to catch up on everything.

Truman was practical and hardworking. He continued receiving briefings from his advisers. But would hard work be enough? Could the little haberdasher from Missouri stand up to Stalin, the fearsome dictator?

One month after Truman’s arrival at the White House, the Allies won the war in Europe. Across the continent, people celebrated. In London, before Buckingham Palace, crowds cheered Winston Churchill. The British Prime Minister was hailed as a hero. Yet despite the euphoria, Churchill looked worn out. The smile on his face was somewhat forced.

In his memoirs, he wrote:

“Fatigued, exhausted, impoverished, yet unafraid—and now victorious. We experienced a moment of supreme emotion. Yet no heart was more burdened with anxiety than mine.”

What weighed so heavily on him? Stalin.

Now that the war in Europe was won, the British were convinced that Stalin would seize the opportunity to install communist regimes wherever he could. Already, in contradiction to the Yalta commitments, the Soviet leader had established a communist regime in Romania. In Poland, six non-communist ministers sat in the government, but every day they had a little less power.

Stalin wanted all of Europe to become communist—not only for ideological reasons but also because he had the mentality of an emperor, a dictator with an imperial mindset.

Churchill tried to warn Truman. The brand-new American president didn’t want to hear any of it. Truman intended to uphold Roosevelt’s commitments and would not listen to anything against his communist ally. Churchill could only hope Truman would open his eyes—soon.

The opportunity came quickly.

On July 16, 1945, Truman’s aircraft landed in Berlin. He arrived in Europe to attend a peace conference. For the first time, he would meet his allies and judge them for himself. The discussions were to take place in Potsdam, a few kilometers from Berlin.

As Truman traveled through the former capital of the Reich, he saw a city reduced to rubble. Only a few gaunt survivors wandered through the ruins. The devastation deeply disturbed him and strengthened his resolve to help rebuild Germany. That evening, he wrote in his diary:

“I have never witnessed a more dreadful sight of suffering. We saw old men, old women, young women carrying whatever they could salvage of their belongings.”

The conference opened the next day, July 17. At Schloss Cecilienhof, Stalin, Truman, and Churchill would meet together for the first and only time. As Truman expected, Churchill was charming. Stalin, according to his advisers, was supposedly trustworthy. But Truman quickly sized him up.

“I can deal with Stalin. He is honest—but as smart as the devil.”

Stalin, for his part, did not trust Truman at all. To him, Truman was still just a small shopkeeper from Missouri. Soviet intelligence had little information about him, and what little they had suggested he was insignificant and lazy—someone they believed could be easily manipulated.

But when Truman said no, it meant no. Against all odds, despite his lack of experience, the American president knew how to stand firm. He was not easily impressed by Stalin. And there was more: Truman felt increasingly confident because he was expecting news that could turn him into the most powerful man on Earth.

At that same moment, in the United States, a top-secret event was unfolding. While Truman negotiated, he awaited eagerly for a coded message.

On the second day of discussions, he received it. The telegram read metaphorically:

“The doctor has returned enthusiastic and confident. The baby is as strong as its big brother. The light in its eyes could be seen from here at high altitude, and I thought I heard its cry all the way from my farm.”

“The baby” referred to Little Boy—the atomic bomb.

For four years, in the greatest secrecy, the world’s best scientists had worked to develop the ultimate weapon. Code name: Trinity. The first atomic test in history was a complete success. Its explosive power equaled 21 kilotons of TNT. Humanity had never seen such destructive force. Now a weapon existed capable of destroying all mankind.

After some hesitation, Truman informed Stalin about it. The news was, of course, unwelcome. It meant the Soviet Union would now feel inferior. Witnesses observed Stalin’s reaction. Stalin, a master actor, simply said: “Oh, you have a powerful bomb? I congratulate you. I hope you use it against Japan.”

But did Stalin really know nothing?

Despite intense American security measures, the Soviets had infiltrated spies into Los Alamos, where the atomic bomb was built. Among them was Klaus Fuchs—a German physicist who had fled Nazism and who, as a convinced communist, also spied for the Soviet Union. For two years, Fuchs delivered to the Soviets every blueprint of the American bomb.

With this information, the USSR began building its own nuclear weapon.

Even so, on July 24, when Stalin learned that the Americans now had a functioning bomb, he was anxious. Stalin hated feeling vulnerable. He summoned everyone involved in the Soviet nuclear project and demanded that the development of a Soviet atomic bomb be accelerated at all costs. The bomb became an obsession for him. Until he had it, he would not feel secure against America.

Relations with Truman began to heat up.

Potsdam also witnessed another kind of explosion. Midway through the conference, Churchill left for London to await election results. As a committed democrat, he accepted the risk. Polls predicted victory; crowds cheered him nationwide. Yet on election morning, he awoke with dread:

“I felt as if a dagger had been thrust into me. The power to shape the future would be denied me.”

His intuition was correct. Against all expectations, Churchill lost. The British chose a new man: Labour leader Clement Attlee. After his victory, Attlee quietly sat in Churchill’s still-warm chair. Around the table, everyone sensed something was off.

Attlee seemed insignificant. Churchill once described him as “a sheep in sheep’s clothing.” Stalin was baffled; he had assumed Churchill would manipulate the elections. For Stalin, that’s what any politician worthy of the job would do.

With Attlee appearing lost and awkward, Stalin focused on Truman. Only two great powers remained: the United States and the Soviet Union. Truman and Stalin now faced each other directly. Their disagreements soon hardened into true opposition.

Five days after Potsdam, Truman made a decision with enormous consequences: The United States would use the atomic bomb against Japan. Tensions with Stalin immediately escalated.

August 6, 1945, early morning. The American bomber Enola Gay reached Japan. At 8:15 a.m., Little Boy was dropped on Hiroshima. A massive atomic mushroom cloud rose above the city. Ground temperatures reached 4,000 degrees Celsius. Seventy thousand people died instantly. The city became a wasteland of ashes. Three days later, Nagasaki suffered the same fate. The world was shocked.

To Stalin, the atomic bombings were a provocation. He believed Truman intended to impress him. He could not understand why the Americans dropped the bomb when, on August 8—as promised—the Soviet Union had entered the war against Japan alongside the U.S.

“To us, the message was clear,” a Soviet official later said. “The bomb was not to defeat Japan quickly but to frighten the Soviet Union and impose American conditions.”

Of course, Truman wanted to end the war quickly and save American lives. But the bomb also sent a message to Stalin: Truman was now master of the game. Stalin wanted to know how far he could push back. He decided to test Truman’s limits.

At Yalta, Stalin had been promised territory in exchange for joining the war against Japan: southern Sakhalin, the Kuril Islands, Port Arthur, and a railway in Manchuria. Now he asked additionally to occupy Hokkaido. In a telegram to Truman, Stalin argued:

“Public opinion in Russia will appreciate that our troops receive a zone of occupation. They will be gravely offended otherwise. I hope my modest request will be granted.”

He later added, in handwriting: “I will not insist.”

Truman was irritated. His reply was terse: “No.” And that was that. Truman expected people to be honest and straightforward. He was—and wanted the same in return. When he realized Stalin was trying to take advantage of him, he adopted a much tougher negotiating stance.

Stalin also shifted gears. He intensified his grip on Europe: forced elections, coups—wherever he could, he installed communist regimes. Poland, Czechoslovakia, Hungary, and Bulgaria soon fell under Soviet control.

This alarming consolidation worried Truman. But he still hesitated about what to do. Then, on February 22, 1946, a telegram landed on his desk—a telegram that changed everything.

Its author was George Kennan, a diplomat stationed in Moscow. Kennan had observed Stalin closely. He understood Stalin’s desire to dominate Eastern Europe and believed there was only one way to stop him: firmness. In a long telegram to Washington, he described how the Soviet regime functioned.

“The Kremlin has a neurotic view of world affairs, born from the Russians’ chronic sense of insecurity. The Russians are impervious to logic of reason but highly sensitive to logic of force.”

Kennan explained that it was useless to try to reassure Stalin; Stalin could not and did not want to be reassured, since fear justified his dictatorship. But he would respect firmness. As soon as the West stood strong, Stalin would back down.

Kennan’s analysis confirmed Truman’s intuition. Truman removed Roosevelt’s former advisers, considered too soft on the Soviets, and promoted new ones. Kennan was called to the White House as a special adviser.

Yet one last challenge remained: convincing the American public to accept this drastic shift in policy. It was delicate, because to Americans, Stalin was still the great ally who had helped defeat Hitler. Wartime propaganda had portrayed him as a friend of children and America’s trusted partner. The propaganda had worked: Stalin was genuinely popular in the U.S.

Truman then had an idea: He would use the prestige of former Prime Minister Churchill to deliver the bad news. Churchill would be thrilled to come to America, especially after his electoral defeat and subsequent depression.

On March 5, 1946, the small town of Fulton, Missouri, brought out flags to welcome Churchill. It was sunny. Truman, greeting Churchill on his home turf, was all smiles. He knew Churchill was about to drop a bombshell—but Truman would pretend he knew nothing.

Minutes later, at Westminster College, Churchill delivered a speech that stunned the audience and shook the world:

“From Stettin in the Baltic to Trieste in the Adriatic, an iron curtain has descended across the continent.”

The Iron Curtain speech caused an uproar. Americans were shocked. Stalin—their great wartime friend—was now portrayed as a threat. Truman’s strategy was brilliant. Churchill’s authority transformed what could have seemed like Truman’s personal hostility into a widely accepted assessment. Soon, Americans who once admired Stalin now viewed him as a dangerous tyrant.

In the Soviet Union, the Fulton speech was seen as a dagger in the back. Stalin was furious. Soviet intellectuals and Kremlin officials attacked Churchill:

“Churchill is the sworn enemy of our country. He is the world’s most anti-Soviet Western leader.”

Europe now had to choose: communism or capitalism. Stalin was ahead. He held Eastern Europe and had influence in Western Europe, where communist ministers held seats in France and Italy. How far would Stalin extend his reach?

Truman realized something crucial: In this global struggle, his enemy was also poverty. Nearly two years after the end of WWII, Europe had not recovered. The continent was on the brink of collapse. Misery was fertile ground for communism.

At the beginning of 1947, Truman sent Senator Mike Mansfield to Europe to assess the situation. Mansfield’s report was grim: clear signs of malnutrition, tuberculosis, disease. In Italy, most of the population lived on a ration of 75–125 grams of bread a day. They ate almost nothing else.

After reading the report, Truman became convinced: If he did not help Europe, he would hand it over to Stalin. Truman then decided on a massive rescue plan for Europe, entrusted to General George Marshall, the new Secretary of State. Raw materials, machinery, and tons of supplies crossed the Atlantic. The Marshall Plan was generous—but also essential for the U.S., which needed to restart its own economy.

You cannot grow rich alone; you need rich partners. If the U.S., enriched by the war, could not trade with impoverished nations, its prosperity would decline. The Marshall Plan was also a political weapon to destabilize Stalin. Aid was offered to all European countries—including those under Soviet control. Eastern nations, like Czechoslovakia and Poland, were also invited.

But ideology prevailed. The Marshall Plan was denounced by the Soviets as a scheme for American domination, and Eastern countries were ordered not to participate. Sixteen Western nations accepted the plan, with France, the UK, and Italy receiving the most aid.

By mid-1947, Churchill’s Iron Curtain had become a reality. One city would soon illustrate the new balance of power: Berlin. The German capital lay in the middle of the Soviet occupation zone, but the city itself was jointly occupied by the U.S., UK, France, and the USSR. All were supposed to help Germany get back on its feet, but they disagreed on how.

The Soviets wanted war reparations, since the USSR was devastated. Under the peace agreements, they dismantled German factories and shipped them east. Entire industrial sites were uprooted. Meanwhile, the Americans rebuilt Germany, as they had promised through the Marshall Plan, giving Germany $16 billion. The Soviets gave nothing—they simply couldn’t.

Western Germany slowly came back to life, while East Berlin remained desolate. The Americans wanted deeper economic reforms; Stalin opposed them. He wanted equal misery on both sides of Berlin, hoping West Berlin would eventually fall under communist influence. This capitalist enclave in the heart of East Germany was intolerable to him.

The Western allies saw only one solution: merge their zones. This would surely enrage Stalin. The question was: would Stalin go to war? Before acting, the West needed intelligence. Thus began the era of espionage.

At the start of the Cold War, the U.S. intelligence services barely existed. During WWII, Roosevelt had created the OSS, but it was dissolved in 1945. From 1945 to 1947, the U.S. had no real intelligence agency. In the summer of 1947, Truman created a new agency: the CIA. Admiral Hillenkoetter became its head.

He had to recruit spies urgently—but fluent Russian speakers were scarce, except among Russians themselves, who couldn’t necessarily be trusted. The Americans then turned to a surprising source: former enemies. Reinhard Gehlen, former Nazi intelligence chief on the Eastern Front, was recruited. He knew the Soviet world well and would become the brain of U.S. espionage in Germany.

Through him, hundreds of former Nazis joined the CIA. The Americans had no qualms about it. The only thing that mattered to Truman was stopping Stalin’s advance. The world had changed. In the Cold War, the enemy was no longer Germany, but the Soviet Union. And those who were extremely anti-communist—such as former Nazis—were now valuable. This was realpolitik.

Facing the CIA, the Soviet secret services—the GRU and the KGB—were also highly active. They had a head start, as their intelligence networks had existed since World War I. Berlin became the capital of espionage. On the streets, in the administration, in the military—spies were everywhere. All, regardless of allegiance, shared the same goal: uncovering the adversary’s plans as quickly as possible.

Espionage became a new style of warfare—one that required no guns. It allowed them to pierce the very heart of the enemy’s ideological system.

As Truman had requested, Gehlen and his men tried to determine how Stalin would react if the Western powers united their occupation zones in Berlin. By late spring 1948, German agents believed they had their answer.

On June 9, Hillenkoetter warned Truman by telegram. According to the head of the CIA, if the Western Allies merged their zones, Stalin would respond by placing obstacles in their way in Berlin and elsewhere in Germany—but without resorting to force. It was the green light the Western powers had been waiting for.

Four days after Hillenkoetter’s telegram, the Americans, British, and French introduced a new currency in their zones: the Deutsche Mark. For Stalin, this capitalist currency was a provocation. He had to react. As the German spies predicted, the Soviet leader chose economic retaliation.

On June 24, 1948, he cut all supply routes from West Germany to West Berlin. Roads, railways, canals—everything was blocked. Two and a half million Berliners were trapped. Without food, they could not survive long.

In Washington, some of Truman’s advisers urged a military response. The American president chose another option: supplying Berlin by air. He did not want to trigger another war with the Soviet Union—far from it. But he also did not want to appear weak. If the Soviets could blockade Berlin without consequence, they could do the same elsewhere.

The idea of an airlift was not Truman’s, but he accepted it because it made sense.

Four days after the blockade began, massive American and British cargo planes flew over Berlin, carrying tons of food, equipment, and the famous CARE packages: bacon, margarine, powdered eggs, chocolate—the taste of America.

What Stalin had not imagined was that the Americans, British, and French would be capable of supplying West Berlin for 11 months, at a rate of 6,000 tons per day. Every day, at Berlin’s three airports, a plane landed every 30 seconds. For an entire year, Berliners lived to the rhythm of aircraft taking turns, day and night, above their heads.

Despite American aid, daily life remained difficult. To survive, people improvised. Gardens appeared in the middle of paved streets. To heat their homes, Berliners used whatever they could find—trees were uprooted; every park bench vanished. In stairwells, people traded anything: coats, bags, shoes. They lacked everything, but they held on.

The Americans were equally determined. And as Gehlen had predicted, Stalin did not order American aircraft to be shot down. The Soviets were not ready for war—especially after losing over 20 million people during WWII.

Realizing he had lost the contest, Stalin lifted the blockade on May 12, 1949. In West Berlin, joy erupted. For Stalin, the defeat was bitter. The small merchant from Missouri had forced the most feared man on earth to bend.

In his memoirs, Truman rejoiced. He knew that in his confrontation with Stalin, he had just scored a decisive point. The blockade had pushed the Germans away from communism. Germany, which had passively waited to see whom to entrust its future to, now leaned toward the Western powers. The opposite of what Stalin wanted.

It sealed reconciliation and friendship between the German and American peoples. These were the men who had ensured West Berlin’s survival.

Fifteen days after the blockade was lifted, the Western Allies created the Federal Republic of Germany. The Soviets retaliated with the German Democratic Republic. The former wartime partners were now officially enemies.

At the White House, Kennan was alarmed. Far-sighted as always, he wrote:

“At the end of the day, our policy on the continent leads us to a situation in which only three outcomes are possible: a collapse of the Soviet Union, a retreat from our position, or a terrible war.”

And the threat of that terrible war grew heavier each day. Stalin had not digested the humiliation of the blockade. He sought revenge—and soon succeeded in turning the tables again.

On August 29, 1949, to the shock of the Western world, the Soviets detonated an atomic bomb in Kazakhstan. The information provided by Fuchs and his fellow spies at Los Alamos had borne fruit.

“Soviet intelligence allowed us to accelerate the creation of our atomic bomb and saved us enormous resources,” a Soviet scientist later recalled. “Our scientists believed that the information shortened the timeline by 5 to 10 years.”

For Truman, the surprise was immense. He had never imagined the war-ravaged USSR could develop a nuclear weapon so quickly. Stalin felt powerful again. The Soviets had regained parity with the United States. The world entered the era of nuclear terror.

The Cold War, as Raymond Aron put it, became “a war impossible to wage, impossible to conclude”—impossible because it would be nuclear, and impossible to end because no peace was reachable. Impossible war, unavoidable peace.

Soon, real conflicts would erupt—but only locally, fought through proxies. Never would American and Soviet blood be shed directly. The risk of general nuclear warfare prevented it.

The first of these postwar conflicts broke out in a small country few Americans or Russians could even locate on a map: Korea. Since 1945, Korea—formerly under Japanese rule—had been split at the 38th parallel. To the south: the Americans. To the north: the Soviets.

From the start, Kim Il-sung, the communist leader of North Korea, sought to reunify his country. Many times he asked Stalin for support. The Soviets always refused—until January 12, 1950. Because of one seemingly small sentence spoken by U.S. Secretary of State Dean Acheson.

That day, in a speech outlining America’s defense perimeter, Acheson said:

“Our defensive perimeter runs from the Aleutians to Japan, passing through the Ryukyus and the Philippines.”

He forgot Korea. A foolish mistake. He listed Taiwan, Tokyo, the Philippines—everything except Korea. It was astonishing for someone as knowledgeable as Acheson. Stalin interpreted it as encouragement.

He told himself that perhaps the Americans had become soft again. Stalin then gave Kim Il-sung the green light.

On June 25, 1950, at 4 a.m., North Korean forces crossed the 38th parallel. Truman, at home in Missouri for the weekend, was informed immediately. He did not hesitate: force must be used to respond.

In his memoirs, he wrote:

“If such a scenario is not stopped in Korea, it will mean the beginning of World War III. These are the same events that provoked World War II.”

The Americans had not expected an attack. They had almost no troops in Korea. North Korea progressed easily and captured Seoul in less than a week. Truman grew extremely worried. How would this end? He wrote to his wife:

“I hope I won’t have to give the order to use our terrible weapons.”

But Truman would not need to use the atomic bomb, because he could rely on one man: General MacArthur—the great hero of the Pacific War, now administering Japan. He knew Asia well and was a brilliant strategist. Within months, MacArthur reversed the momentum. By November 1950, American forces nearly occupied all of North Korea, approaching the Chinese border.

The Cold War risked becoming very hot. Since 1949, neighboring China had been communist. Mao sent 500,000 Chinese “volunteers” to aid his North Korean comrades. Mao also understood the Cold War well. He intervened indirectly—not as a state, but through “volunteers,” maintaining plausible denial.

For Truman, the situation was extremely stressful. After months of pressure, he was psychologically exhausted. In his diary, he wrote:

“What a hell of a thing it is to be President of the strongest nation on earth! I’d rather be a farmer in Missouri.”

He no longer called the White House anything other than “the Great White Jail.”

In Korea, the war became bogged down. Unexpectedly, the conflict would soon end because Stalin disappeared.

March 1, 1953—Stalin’s dacha in Kuntsevo, near Moscow. The Soviet dictator now lived reclusively, trapped in paranoid delusion, terrified of assassination. That night, heavily intoxicated, he suffered a cerebral hemorrhage. For ten hours he lay dying, but no one dared enter his room. Fear of punishment paralyzed them. Stalin suffered alone. His personal doctors were in prison.

He might have survived. When his old associates—Khrushchev, Beria, Voroshilov, Malenkov—arrived, they did nothing. They feared being blamed. Doctors were brought in, but they were terrified. They did not even dare write a diagnosis. KGB agents warned them: “Comrades, be careful what you write and what you discover.”

Lacking proper care, Stalin died after four days of agony, on March 5, 1953.

Within hours, five million people flooded into Moscow to see the remains of the man who had held power over life and death for a quarter century. Some who hated Stalin prayed: “Thank God—finally he’s gone.” Others, who saw him as a kind of deity, were stunned that their god could be mortal.

A third feeling dominated all: What happens now?

The whole world was shocked. In Moscow, London, and Washington, many hoped that the death of the Soviet dictator would ease tensions. But expectations were quickly disappointed. Eight years of continuous confrontation between America and the Soviet Union had shaped the world too deeply to reverse. The Cold War, born under Stalin and solidified under Truman, would dominate global affairs and shake nations for nearly forty years.