The republic that Sun Yat-sen and his associates envisioned evolved slowly. The revolutionists lacked an army, and the power of Yuan Shikai began to outstrip that of parliament. Yuan revised the constitution at will and became dictatorial. In August 1912 a new political party was founded by Song Jiaoren ( 1882-1913), one of Sun's associates. The party, the Guomindang ( Kuomintang or KMT--the National People's Party, frequently referred to as the Nationalist Party), was an amalgamation of small political groups, including Sun's Tongmeng Hui . In the national elections held in February 1913 for the new bicameral parliament, Song campaigned against the Yuan administration, and his party won a majority of seats. Yuan had Song assassinated in March; he had already arranged the assassination of several pro-revolutionist generals. Animosity toward Yuan grew. In the summer of 1913 seven southern provinces rebelled against Yuan. When the rebellion was suppressed, Sun and other instigators fled to Japan. In October 1913 an intimidated parliament formally elected Yuan president of the Republic of China, and the major powers extended recognition to his government. To achieve international recognition, Yuan Shikai had to agree to autonomy for Outer Mongolia and Xizang . China was still to be suzerain, but it would have to allow Russia a free hand in Outer Mongolia and Britain continuance of its influence in Xizang.

In November Yuan Shikai, legally president, ordered the Guomindang dissolved and its members removed from parliament. Within a few months, he suspended parliament and the provincial assemblies and forced the promulgation of a new constitution, which, in effect, made him president for life. Yuan's ambitions still were not satisfied, and, by the end of 1915, it was announced that he would reestablish the monarchy. Widespread rebellions ensued, and numerous provinces declared independence. With opposition at every quarter and the nation breaking up into warlord factions, Yuan Shikai died of natural causes in June 1916, deserted by his lieutenants.

After Yuan Shikai's death, shifting alliances of regional warlords fought for control of the Beijing government. The nation also was threatened from without by the Japanese. When World War I broke out in 1914, Japan fought on the Allied side and seized German holdings in Shandong Province. In 1915 the Japanese set before the warlord government in Beijing the so-called Twenty-One Demands, which would have made China a Japanese protectorate. The Beijing government rejected some of these demands but yielded to the Japanese insistence on keeping the Shandong territory already in its possession. Beijing also recognized Tokyo's authority over southern Manchuria and eastern Inner Mongolia. In 1917, in secret communiques, Britain, France, and Italy assented to the Japanese claim in exchange for the Japan's naval action against Germany.
In 1917 China declared war on Germany in the hope of recovering its lost province, then under Japanese control. But in 1918 the Beijing government signed a secret deal with Japan accepting the latter's claim to Shandong. When the Paris peace conference of 1919 confirmed the Japanese claim to Shandong and Beijing's sellout became public, internal reaction was shattering. On May 4, 1919, there were massive student demonstrations against the Beijing government and Japan. The political fervor, student activism, and iconoclastic and reformist intellectual currents set in motion by the patriotic student protest developed into a national awakening known as the May Fourth Movement . The intellectual milieu in which the May Fourth Movement developed was known as the New Culture Movement and occupied the period from 1917 to 1923. The student demonstrations of May 4, 1919 were the high point of the New Culture Movement, and the terms are often used synonymously. Students returned from abroad advocating social and political theories ranging from complete Westernization of China to the socialism that one day would be adopted by China's communist rulers.

The May Fourth Movement helped to rekindle the then-fading cause of republican revolution. In 1917 Sun Yat-sen had become commander-in-chief of a rival military government in Guangzhou in collaboration with southern warlords. In October 1919 Sun reestablished the Guomindang to counter the government in Beijing. The latter, under a succession of warlords, still maintained its facade of legitimacy and its relations with the West. By 1921 Sun had become president of the southern government. He spent his remaining years trying to consolidate his regime and achieve unity with the north. His efforts to obtain aid from the Western democracies were ignored, however, and in 1921 he turned to the Soviet Union, which had recently achieved its own revolution. The Soviets sought to befriend the Chinese revolutionists by offering scathing attacks on "Western imperialism." But for political expediency, the Soviet leadership initiated a dual policy of support for both Sun and the newly established Chinese Communist Party ( CCP). The Soviets hoped for consolidation but were prepared for either side to emerge victorious. In this way the struggle for power in China began between the Nationalists and the Communists. In 1922 the Guomindang-warlord alliance in Guangzhou was ruptured, and Sun fled to Shanghai . By then Sun saw the need to seek Soviet support for his cause. In 1923 a joint statement by Sun and a Soviet representative in Shanghai pledged Soviet assistance for China's national unification. Soviet advisers--the most prominent of whom was an agent of the Comintern, Mikhail Borodin--began to arrive in China in 1923 to aid in the reorganization and consolidation of the Guomindang along the lines of the Communist Party of the Soviet Union. The CCP was under Comintern instructions to cooperate with the Guomindang, and its members were encouraged to join while maintaining their party identities. The CCP was still small at the time, having a membership of 300 in 1922 and only 1,500 by 1925. The Guomindang in 1922 already had 150,000 members. Soviet advisers also helped the Nationalists set up a political institute to train propagandists in mass mobilization techniques and in 1923 sent Chiang Kai-shek ( Jiang Jieshi in pinyin), one of Sun's lieutenants from Tongmeng Hui days, for several months' military and political study in Moscow. After Chiang's return in late 1923, he participated in the establishment of the Whampoa ( Huangpu in pinyin) Military Academy outside Guangzhou, which was the seat of government under the Guomindang-CCP alliance. In 1924 Chiang became head of the academy and began the rise to prominence that would make him Sun's successor as head of the Guomindang and the unifier of all China under the right-wing nationalist government.
Sun Yat-sen died of cancer in Beijing in March 1925, but the Nationalist movement he had helped to initiate was gaining momentum. During the summer of 1925, Chiang, as commander-in-chief of the National Revolutionary Army, set out on the long-delayed Northern Expedition against the northern warlords. Within nine months, half of China had been conquered. By 1926, however, the Guomindang had divided into left- and right-wing factions, and the Communist bloc within it was also growing. In March 1926, after thwarting a kidnapping attempt against him, Chiang abruptly dismissed his Soviet advisers, imposed restrictions on CCP members' participation in the top leadership, and emerged as the preeminent Guomindang leader. The Soviet Union, still hoping to prevent a split between Chiang and the CCP, ordered Communist underground activities to facilitate the Northern Expedition, which was finally launched by Chiang from Guangzhou in July 1926.

In early 1927 the Guomindang-CCP rivalry led to a split in the revolutionary ranks. The CCP and the left wing of the Guomindang had decided to move the seat of the Nationalist government from Guangzhou to Wuhan. But Chiang, whose Northern Expedition was proving successful, set his forces to destroying the Shanghai CCP apparatus and established an anti-Communist government at Nanjing in April 1927. There now were three capitals in China: the internationally recognized warlord regime in Beijing; the Communist and left-wing Guomindang regime at Wuhan ; and the right-wing civilian-military regime at Nanjing, which would remain the Nationalist capital for the next decade.

The Comintern cause appeared bankrupt. A new policy was instituted calling on the CCP to foment armed insurrections in both urban and rural areas in preparation for an expected rising tide of revolution. Unsuccessful attempts were made by Communists to take cities such as Nanchang , Changsha , Shantou , and Guangzhou, and an armed rural insurrection, known as the Autumn Harvest Uprising, was staged by peasants in Hunan Province. The insurrection was led by Mao Zedong ( 1893-1976), who would later become chairman of the CCP and head of state of the People's Republic of China. Mao was of peasant origins and was one of the founders of the CCP.

But in mid-1927 the CCP was at a low ebb. The Communists had been expelled from Wuhan by their left-wing Guomindang allies, who in turn were toppled by a military regime. By 1928 all of China was at least nominally under Chiang's control, and the Nanjing government received prompt international recognition as the sole legitimate government of China. The Nationalist government announced that in conformity with Sun Yat-sen's formula for the three stages of revolution--military unification, political tutelage, and constitutional democracy--China had reached the end of the first phase and would embark on the second, which would be under Guomindang direction.

The decade of 1928-37 was one of consolidation and accomplishment by the Guomindang . Some of the harsh aspects of foreign concessions and privileges in China were moderated through diplomacy. The government acted energetically to modernize the legal and penal systems, stabilize prices, amortize debts, reform the banking and currency systems, build railroads and highways, improve public health facilities, legislate against traffic in narcotics, and augment industrial and agricultural production. Great strides also were made in education and, in an effort to help unify Chinese society, in a program to popularize the national language and overcome dialectal variations. The widespread establishment of communications facilities further encouraged a sense of unity and pride among the people.

There were forces at work during this period of progress that would eventually undermine the Chiang Kai-shek government. The first was the gradual rise of the Communists.
Mao Zedong , who had become a Marxist at the time of the emergence of the May Fourth Movement (he was working as a librarian at Beijing University), had boundless faith in the revolutionary potential of the peasantry. He advocated that revolution in China focus on them rather than on the urban proletariat, as prescribed by orthodox Marxist-Leninist theoreticians. Despite the failure of the Autumn Harvest Uprising of 1927, Mao continued to work among the peasants of Hunan Province. Without waiting for the sanction of the CCP center, then in Shanghai, he began establishing peasant-based soviets (Communist-run local governments) along the border between Hunan and Jiangxi provinces. In collaboration with military commander Zhu De ( 1886-1976), Mao turned the local peasants into a politicized guerrilla force. By the winter of 1927-28, the combined "peasants' and workers'" army had some 10,000 troops.

Mao's prestige rose steadily after the failure of the Comintern-directed urban insurrections. In late 1931 he was able to proclaim the establishment of the Chinese Soviet Republic under his chairmanship in Ruijin Jiangxi Province. The Soviet-oriented CCP Political Bureau came to Ruijin at Mao's invitation with the intent of dismantling his apparatus. But, although he had yet to gain membership in the Political Bureau, Mao dominated the proceedings.

In the early 1930s, amid continued Political Bureau opposition to his military and agrarian policies and the deadly annihilation campaigns being waged against the Red Army by Chiang Kai-shek's forces, Mao's control of the Chinese Communist movement increased. The epic Long March of his Red Army and its supporters, which began in October 1934, would ensure his place in history. Forced to evacuate their camps and homes, Communist soldiers and government and party leaders and functionaries numbering about 100,000 (including only 35 women, the spouses of high leaders) set out on a circuitous retreat of some 12,500 kilometers through 11 provinces, 18 mountain ranges, and 24 rivers in southwest and northwest China. During the Long March, Mao finally gained unchallenged command of the CCP, ousting his rivals and reasserting guerrilla strategy. As a final destination, he selected southern Shaanxi Province, where some 8,000 survivors of the original group from Jiangxi Province (joined by some 22,000 from other areas) arrived in October 1935. The Communists set up their headquarters at Yan'an , where the movement would grow rapidly for the next ten years. Contributing to this growth would be a combination of internal and external circumstances, of which aggression by the Japanese was perhaps the most significant. Conflict with Japan, which would continue from the 1930s to the end of World War II, was the other force (besides the Communists themselves) that would undermine the Nationalist government.

Few Chinese had any illusions about Japanese designs on China. Hungry for raw materials and pressed by a growing population, Japan initiated the seizure of Manchuria in September 1931 and established ex-Qing emperor Puyi as head of the puppet regime of Manchukuo in 1932. The loss of Manchuria, and its vast potential for industrial development and war industries, was a blow to the Nationalist economy. The League of Nations, established at the end of World War I, was unable to act in the face of the Japanese defiance. The Japanese began to push from south of the Great Wall into northern China and into the coastal provinces. Chinese fury against Japan was predictable, but anger was also directed against the Guomindang government, which at the time was more preoccupied with anti-Communist extermination campaigns than with resisting the Japanese invaders. The importance of "internal unity before external danger" was forcefully brought home in December 1936, when Nationalist troops (who had been ousted from Manchuria by the Japanese) mutinied at Xi'an . The mutineers forcibly detained Chiang Kai-shek for several days until he agreed to cease hostilities against the Communist forces in northwest China and to assign Communist units combat duties in designated anti-Japanese front areas.
The Chinese resistance stiffened after July 7, 1937, when a clash occurred between Chinese and Japanese troops outside Beijing (then renamed Beiping ) near the Marco Polo Bridge. This skirmish not only marked the beginning of open, though undeclared, war between China and Japan but also hastened the formal announcement of the second Guomindang-CCP united front against Japan. The collaboration took place with salutary effects for the beleaguered CCP. The distrust between the two parties, however, was scarcely veiled. The uneasy alliance began to break down after late 1938, despite Japan's steady territorial gains in northern China, the coastal regions, and the rich Chang Jiang Valley in central China. After 1940, conflicts between the Nationalists and Communists became more frequent in the areas not under Japanese control. The Communists expanded their influence wherever opportunities presented themselves through mass organizations, administrative reforms, and the land- and tax-reform measures favoring the peasants--while the Nationalists attempted to neutralize the spread of Communist influence.

At Yan'an and elsewhere in the "liberated areas," Mao was able to adapt Marxism-Leninism to Chinese conditions. He taught party cadres to lead the masses by living and working with them, eating their food, and thinking their thoughts. The Red Army fostered an image of conducting guerrilla warfare in defense of the people. Communist troops adapted to changing wartime conditions and became a seasoned fighting force. Mao also began preparing for the establishment of a new China. In 1940 he outlined the program of the Chinese Communists for an eventual seizure of power. His teachings became the central tenets of the CCP doctrine that came to be formalized as Mao Zedong Thought. With skillful organizational and propaganda work, the Communists increased party membership from 100,000 in 1937 to 1.2 million by 1945.

In 1945 China emerged from the war nominally a great military power but actually a nation economically prostrate and on the verge of all-out civil war. The economy deteriorated, sapped by the military demands of foreign war and internal strife, by spiraling inflation, and by Nationalist profiteering, speculation, and hoarding. Starvation came in the wake of the war, and millions were rendered homeless by floods and the unsettled conditions in many parts of the country. The situation was further complicated by an Allied agreement at the Yalta Conference in February 1945 that brought Soviet troops into Manchuria to hasten the termination of war against Japan. Although the Chinese had not been present at Yalta, they had been consulted; they had agreed to have the Soviets enter the war in the belief that the Soviet Union would deal only with the Nationalist government. After the war, the Soviet Union, as part of the Yalta agreement's allowing a Soviet sphere of influence in Manchuria, dismantled and removed more than half the industrial equipment left there by the Japanese. The Soviet presence in northeast China enabled the Communists to move in long enough to arm themselves with the equipment surrendered by the withdrawing Japanese army. The problems of rehabilitating the formerly Japanese-occupied areas and of reconstructing the nation from the ravages of a protracted war were staggering, to say the least.

During World War II, the United States emerged as a major actor in Chinese affairs. As an ally it embarked in late 1941 on a program of massive military and financial aid to the hard-pressed Nationalist government. In January 1943 the United States and Britain led the way in revising their treaties with China, bringing to an end a century of unequal treaty relations. Within a few months, a new agreement was signed between the United States and China for the stationing of American troops in China for the common war effort against Japan. In December 1943 the Chinese exclusion acts of the 1880s and subsequent laws enacted by the United States Congress to restrict Chinese immigration into the United States were repealed.
The wartime policy of the United States was initially to help China become a strong ally and a stabilizing force in postwar East Asia. As the conflict between the Nationalists and the Communists intensified, however, the United States sought unsuccessfully to reconcile the rival forces for a more effective anti-Japanese war effort. Toward the end of the war, United States Marines were used to hold Beiping and Tianjin against a possible Soviet incursion, and logistic support was given to Nationalist forces in north and northeast China.

Through the mediatory influence of the United States a military truce was arranged in January 1946, but battles between Nationalists and Communists soon resumed. Realizing that American efforts short of large-scale armed intervention could not stop the war, the United States withdrew the American mission, headed by General George C. Marshall, in early 1947. The civil war, in which the United States aided the Nationalists with massive economic loans but no military support, became more widespread. Battles raged not only for territories but also for the allegiance of cross sections of the population.

Belatedly, the Nationalist government sought to enlist popular support through internal reforms. The effort was in vain, however, because of the rampant corruption in government and the accompanying political and economic chaos. By late 1948 the Nationalist position was bleak. The demoralized and undisciplined Nationalist troops proved no match for the People's Liberation Army (PLA or ). The Communists were well established in the north and northeast. Although the Nationalists had an advantage in numbers of men and weapons, controlled a much larger territory and population than their adversaries, and enjoyed considerable international support, they were exhausted by the long war with Japan and the attendant internal responsibilities. In January 1949 Beiping was taken by the Communists without a fight, and its name changed back to Beijing. Between April and November, major cities passed from Guomindang to Communist control with minimal resistance. In most cases the surrounding countryside and small towns had come under Communist influence long before the cities. After Chiang Kai-shek and a few hundred thousand Nationalist troops fled from the mainland to the island of Taiwan, there remained only isolated pockets of resistance. In December 1949 Chiang proclaimed Taipei , Taiwan , the temporary capital of China.