The most important question facing the new Chinese leadership at its recent party congress has not been resolved. It is whether the military is to be allowed to grab the lion's share of the nation's resources to build a powerful war machine, on the supposed grounds that war with Russia is imminent. If they win the argument, one result of a huge arms buildup could be to increase the tension between Russia and China to the point at which a jumpy Kremlin, engaged in its own succession struggle, might decide to intervene militarily before the threat becomes too real.

A debate on some such action has been in progress in the Kremlin for a long time, and in the late 1060s Moscow even hinted to the United States that the two should act together on the matter before China plunged the world into a nuclear war. But the China hawks in the Kremlin have always lost the argument in the past, because China's army, for all its massive strength in numbers, was a defensive army and did not have the modern arms to make it a serious military threat.

The other side of this question is whether the funds the Chinese military is demanding are to go instead to develop the country economically. If China's agriculture does not get the resources it needs so badly, the country's population may soon outstrip food production. If China's industry does not get the resources to build the production machinery that would bring it rapidly into the modern world, the country will begin to come apart at its seams.

The signs of the debate on this question that have appeared between the lines of the Chinese press since the death of Mao seemed to suggest that the argument might be resolved at the party congress. But the speech by the party's new leader, Hua Kuo-feng, evaded the issue and studiously avoided any of the sharper and more clear-cut formulas on the subject that have come up during the debate. He mentioned, but without any undue emphasis, the now ritual formula calling for the modernization of both industry and defense, in an obvious effort to play down the whole issue, or to temporize while the policy struggle goes on.

Some observers believe they can detect a victory for the military faction, or at least an important role for it, in the composition of the new Politburo, which has nine more or less full-time military members out of a total of 23, but this is a questionable interpretation. It is the five-member inner core of the Politburo - a new Gang of Five if ever there was one - that holds the real power and here the influence of the military is by no means overwhelming.

The No. 2 man in order of precedence, Marshal Yeh Chien-ying, is indeed largely responsible for Hua's survival as party chairman, having swung the army's military support behind him. But the venerable marshal is, at 80, hardly likely or able to take an effective part in the kind of infighting by which Chinese leadership is usually decided.

The No. 3 man, Teng Hsiao-ping, overthrown by the Gang of Four and only now fully restored to power after much delay, has regained his title of chief of staff, but he is primarly a political administrator. He got himself appointed chief of staff in the first place as a political ploy designed to secure the army's support in his bid for power. But his primary interest is in economic development, and he has given a number of indications that he regards it as the most important item on China's agenda, while at the same time paying lip service to the army's demands.

The No. 4 man, Li Hsien-nien, is the senior deputy premier in charge of economic planning, and his institutional commitment to economic development is certainly greater than to a crash arms drive. The No. 5 man, Gen. Wang Tung-hsing, is an army man only in the sense that he was commander of the Mao bodyguard who, at the decisive moment in the struggle that followed Mao's death, threw this weight behind Hua and supplied the men who arrested the Gang of Four, as well as their key followers. But he is not a military leader of any consequence.

The military weight of the Gang of Five is thus somewhat less than appearances suggest, and this is also true of the larger Politburo, some of whose military members are old, not to say decrepit.

But while the influence of the army faction favoring a rapid arms buildup is not decisive at present, it could still play a crucial role in the struggle for power now under way. Even within the Gang of Five, there is obviously tension between the two most powerful, for Hua Kuo-feng has been largely responsible for delaying Teng's full return to power, just as he had earlier been partly responsible for Teng's ouster, at the time of the Peking riots last year. There is potential tension, too, between Hua and Wang Tung-hsing. Because they are the youngest of the top leadership, the struggle for the long-term succession would have to be fought out between them. If this is preceded by a struggle between Hua and Teng, then Wang is likely to give his support to Teng in order to weaken his more dangerous rival.

Teng, who has given some early signs of looking for an accommodation with Moscow, may be responsible for the comparatively conciliatory tone of Hua's invitation to the Soviet Union to restore normal relations with China. If this materializes, then the pressure on the Peking Politburo to proceed with a rapid arms buildup could be defeated more easily by the faction that favors all-out economic development. The struggle on the arms issue is closely linked to the debate on how Peking should proceed with the Soviet Union - and, by the same token, with the United States.