CHRONICA CHRONICA
← Back to The US-China Great Game: A Century of Two Powers

From Alliance to Enmity — World War II and the Chinese Revolution

Facing a common enemy in Japan, America and China became allies. But when the war ended, revolution swept China, and the newly born People's Republic of China traded fire directly with America on the Korean Peninsula. This is the story of a sudden reversal, from friends to foes, in the span of just a few years.

June 12, 2026

In the skies over China in 1941, there was a strange flock of aircraft.

Across their noses were painted the gaping mouths of sharks. At the controls were American pilots. They were a volunteer air group assembled at China’s request, a unit later known as the Flying Tigers. Against the aircraft of the Japanese military, they defended the skies of China.

The two great powers that had eyed each other warily across the Pacific now truly stood side by side. For they had a common enemy: Japan. But this honeymoon would not last long. By the time the war ended, China itself would have transformed into an entirely different country.

Facing a Common Enemy

As the war between Japan and China sank into a quagmire, America supported China.

The Nationalist government led by Chiang Kai-shek had moved its capital inland to Chongqing and kept up its resistance. For a China whose sea supply routes had been severed, the lifeline was a single mountain road that ran up from Burma. America supported this supply route, known as the Burma Road, with materiel, and the Flying Tigers guarded the skies above it.

In December 1941, when Japan attacked Pearl Harbor, America and China formally became members of the Allies, fighting Japan together. The partner it had once shut out as immigrants and pressed to open its market, America now joined in alliance. Within American society, China was portrayed as a brave ally fighting at their side. A China that tied down the bulk of the Japanese army across its vast continent was indispensable to American strategy. In 1943, the Chinese Exclusion Act, which had stood for more than half a century, was at last repealed, and a major reason was the need to sustain the morale of an ally in wartime.

In this period, American affection for China reached one of its peaks. Chiang Kai-shek’s wife, Soong Mei-ling, addressed the US Congress, appealing in fluent English for support in the fight against Japan and captivating her audience. Magazines and newspapers repeatedly carried the image of a China bravely standing up to the invader. The sense of mission to guide and help China, smoldering since the 19th century, bloomed beautifully for a moment on the stage of war.

Yet this alliance bore a shadow from the start. The Nationalist government that America supported was riddled with corruption and internal strife. And beneath its feet, another China was growing: the Chinese Communist Party led by Mao Zedong.

Revolution, and a New China

When Japan surrendered, China plunged into civil war without a moment’s rest.

The Nationalists and the Communists. The two forces that had joined hands during the war against Japan now clashed over control of China. America backed the Nationalist government, but the Communists put down deep roots in the countryside and spread their support among the people. The tide of war gradually shifted to the Communist side. In April 1949, Communist forces took Nanjing, the capital of the Nationalist government.

  1. 1941

    The Flying Tigers fight the Japanese in China's skies. Late that year, the attack on Pearl Harbor brings the US and China into the Allies

  2. 1943

    The Chinese Exclusion Act, in force for more than half a century, is repealed

  3. 1949

    On October 1, Mao Zedong proclaims the founding of the People's Republic of China. Chiang Kai-shek retreats to Taiwan

  4. 1950

    The Korean War breaks out. In October, the Chinese People's Volunteer Army enters the war and clashes with US forces

  5. 1953

    On July 27, the Korean Armistice Agreement is signed at Panmunjom

And on October 1, 1949, standing on the rostrum at Tiananmen in Beijing, Mao Zedong proclaimed the founding of the People’s Republic of China. Mao became chairman of the new state, and Zhou Enlai became premier, running its day-to-day affairs. The defeated Chiang Kai-shek crossed to the island of Taiwan with his government and army. It was the moment one China split in two across the strait.

The newly born People’s Republic of China chose the path of joining hands with the Soviet Union. Mao visited Moscow and signed a treaty of alliance with Stalin. On the world map of the Cold War, China stood clearly on the opposite side from America. The two great powers that, only a few years earlier, had fought Japan shoulder to shoulder now divided to either side of an ideological wall.

Within the United States, a witch-hunt-like inquisition began over who was responsible for losing China. Diplomats and experts who had reported China’s reality candidly were driven from their posts as having been soft on communism. As a result, the American government lost its capacity to understand China coolly, and the tendency to see the other side as a more monolithic threat than it really was grew stronger. Misunderstanding was thus built into the institutions themselves.

Clash on the Korean Peninsula

And so the two nations would at last trade fire directly. The stage was the Korean Peninsula.

On June 25, 1950, North Korea invaded the South, and the Korean War began. America organized a UN force and counterattacked, then reversed the course of the war in a single stroke with the Inchon landing in September. The UN force pushed north and closed in on the Yalu River, which flowed along the border with China.

At this advance, the newly born China felt a strong sense of crisis. American troops arriving right across its border was a threat the new government could not sit and watch. In October 1950, China sent in the People’s Volunteer Army. Led by Peng Dehuai, the Chinese forces collided head-on with the UN force.

The Korean War carved a deep wound into US-China relations. America came to regard China as a dangerous Communist power tied to the Soviet Union. China, for its part, remembered its experience of fighting the world’s strongest army to a standstill as a source of pride for the new nation.

Into Twenty Years of Silence

After the fighting ceased, what remained between the two nations was a long, thick wall.

America continued to recognize the Nationalist government on Taiwan as the legitimate government of China and refused to recognize the People’s Republic in Beijing as a state. There were no diplomatic relations, no trade, and no movement of people. Facing each other across the Pacific, the two great powers glared at one another as enemies. That state of affairs would continue for more than twenty years.

The story that began with the asymmetric meeting at the close of the 19th century, having passed through the fleeting closeness of alliance, had now arrived at complete enmity. Hope and goodwill alike seemed to have been drowned out before the logic of the Cold War.

But history does not move so simply. In time, when a serious rift would run between China and the Soviet Union, America and China would face each other once more, in a way no one had foreseen. Just as a common enemy had once bound the two nations together, yet another common enemy would begin to thaw their frozen relationship.

Was this article helpful?

If you enjoyed this story —

X LINE

Sources & references