Marxism became a force in China through men and literature and money and arms reaching China by the sea route, as have most Western things. Its position reflected, however, the facts that Russia is China's greatest neighbor and that the Russo-Chinese land frontier is one of the longest in the world. China is much nearer to San Francisco, in terms of shipping costs and speed of connections, than it is to Leningrad, but the appearance of closer proximity to the latter played a considerable role. The Nationalist-Communist coalition[4] was the result of the impact of Marxism from Russia upon China proper. The Communists entered as allies, not as leaders. The period of Nationalist-Communist cooperation lasted because the practical projects of the two revolutionary parties lay in a common direction. The gradual shift in the role of the Communists from advisers and allies to teachers and masters led to the break between the two organizations. How did this shift develop? From the Marxian standpoint it was the move of a party leadership which was bound by a true ideology, that of dialectic materialism. Whatever the ethics of broken individual pledges, there is no question that the Communists were justified according to their own beliefs in abandoning the Nationalists when the Nationalists ceased positive revolutionary action and began a Nationalist reconstitution. The Communists felt themselves bound to take up the standards of the revolution and proceed against Nationalists as against others. There was no room in the Marxian ideology for anything but the officially approved Communist Party; there was no ground for conceding that the Nationalists might be wise in calling a breathing spell. The Kuomintang leaders, on the other hand, had every reason to feel aggrieved at the Communists. The Communists had come to help the Chinese revolutionaries in their struggle for national liberation and to bring about a common front against imperialism in the Far East. When the revolution of national liberation was more than half accomplished, the Communists had increased their following to such an extent that they regarded the Nationalist alliance as a mere episode in the growth of Marxian power in China. Marxists had come to help the cause of Sun Yat-sen; Marxism was spread to fight and undo it. The sobering shock of a grasp on power sent the Nationalists into relative conservatism. An eminent Chinese writer has suggested the change of mood: Our imagination was fired, our enthusiasm was kindled; thousands of young men have fled from home and school from the outermost provinces to join the Nationalist forces; they have toiled and they have sweated, and thousands have gladly laid down their lives on the altar of Nationalism that their dream of a regenerated and redeemed China might come true. But, alas!... The war has ended--so has all idealism.[5]