The idea that China and Europe may join forces to threaten Russia has again become the subject of serious concern in Moscow. The Kremlin is alarmed by signs that West European countries are proposing to sell aircraft and other advanced weapons to China. Moscow sees this as the first step in a possible alliance between China and Western Europe that may pose a military threat to Russia much sooner than some Soviet strategists have expected. "Peking is in a hurry," says Pravda.

The Chinese press speaks of the possible purchase by China of up to 300 jump-jet Harriers from Britain, 200 French Mirage fighters, helicopters from Germany, and other weapons from Sweden. And negotiations on some of these deals have indeed begun. The arms sales would be confined to Europe. Secretary of State Cyrus Vance says that "it would be a great mistake" for the United States to provide arms to China - and he has presumably sought to reassure the Kremlin on this point. Moscow has welcomed President Carter's remark that he hoped to develop cooperation with China in a way that would not be directed against the Soviet Union. Carter, Moscow Radio said, was taking into consideration the fact that any U.S. attempt to play on the differences between Moscow and Peking could boomerang against the United States.

But what pleases Moscow displeases Peking. While China insists that it does not want U.S. arms, it also regards such assurances to the Kremlin as a sign of weakness, which would make Washington an unreliable partner in any showdown with the Kremlin. Peking has lately listed dozens of such signs in the course of a press compaign designed to represent the United States as an irresolute, selfish, Munich-style appeaser of the Soviet Union. The purpose of the campaign is not simply to denigrate the United States, but also to show that Peking's options are not limited to relying on Washington. The alternative to which Peking has devoted most attention, at least in public, is the European option.

At various times Peking has accorded different degrees of emphasis to the various options open to it, depending on the shifts in its internal power struggle and in its debate on what China's foreign policy should be. The emphasis is now on "uniting" with Europe, but the debate is far from resolved. Indeed, the European option is being urged most strongly in Chinese press articles, which are themselves part of the debate.

On the surface, the articles are a reply to misgivings about China's foreign policy voiced by its only European ally, Albania. But, as the People's Daily says, in China, too, "there are persons who frantically oppose Chairman Mao's theory of three worlds," on which the European option is based. It describes them as members of the "Gang of Four," but it is clear that the debate is taking place among the members of the present leadership.

The European option is seen by Peking as involving a military understanding that would keep Russia in check. If Moscow wanted to move against Europe, it would have to reckon with action by China on its other flank. If it wanted to move against China, it would have to expect action by Europe. Peking's calls for "uniting" with Europe are accompanied by dire reminders of what happened when Europe itself failed to unite against Hitler. The "main reason" he succeeded, it insists, is to be found in the failure of the countries threatened by him to "unite for joint defense." But how can Europe and China unite for defense?

The answer is given by Moscow, which sees a right-wing, militarily powerful West Germany as the leader of a future united Europe. The Moscow Literary Gazette speaks of visits to China by "retired" German generals and active politicians whose purpose was "to acquire China as an ally" against the Soviet Union. It sees their visit as paralleling the activities of German generals before World War II, when they were "preparing the Chinese army for the moment when the Wehrmacht would attack the Soviet Union, and then use it to create a second anti-Soviet front, in Asia."

There are certainly those both in the West and in Peking who see the future security of their countries in terms of an anti-Soviet alliance. But the Kremlin has repeatedly warned Europe that any anti-Soviet agreement it makes with China could damage detente beyond repair. The United States has taken such warnings to heart, and Europe is also unlikely to ignore them - even though it might well sell China some modern weapons.

But Europe will hardly supply enough weapons to China to make a real difference in its defense posture. Nor can China be sure that Europe, held in check by Soviet nuclear missiles, would be much help to it in a crisis. This is what must be worrying those in Peking who look askance at the European option. Peking has rejected the U.S. option partly because it thought that Washington did not have the gumption to stand up to the Kremlin. It is hardly likely to decide in the long run that Europe could prove a more steadfast ally.

The strong advocacy of the European option in the Peking press is really a reply to those Chinese leaders who question its feasibility. The criticism of U.S. "appeasement" constitutes a rejection of the U.S. option by Peking. With both these alternatives under attack, some of the Chinese leaders are giving increasing attention, to judge from signs in the Peking press, to a third option - reconciliation with the Soviet Union.