PRESIDENT TITO of Yugoslavia has landed, heavily, in Havana to be greeted, cooly, by Fidel Castro. President Tito arrived early and anxiously at the conference of nonaligned nations to try to forestall its seduction by the Russophile element that the Cubans are leading. According to Cuba, the Soviet Union is the best and truest friend of the Third World since the Soviets are the historic enemy of colonialism and imperialism. That opinion gets progressively more implausible as you get closer to Eastern Europe. President Tito, as an Eastern European, wishes to inject a degree of realism into the proceedings.

You could argue that the declarations and resolutions by the 89 nations represented at Havana constitute nothing more than symbolic gestures. But symbolism makes a difference. These meetings build an influential consensus among the governments that support them. If the Cubans succeed in imposing their version of nonalignment onto the movement, they will enhance the Soviets' respectability most usefully in many parts of the world.

But President Tito regards himself, not unreasonably, as the holder of nonalignment's trademarks and copyrights. He is the survivor of the three presidents -- with India's Nehru and Egypt's Nasser -- who founded the movement 18 years ago. Now, at the age of 87, he does not intend to let the Russians run away with it.

While the Cuban tilt to the East is the central issue, there is also the matter of the Camp David agreements. Some of the Arabs are pushing a strategy to punish Egypt for having signed them. Egypt's defenders point out that Camp David has very little to do with the principles of nonalignment. But it has a lot to do with the interests of some of the nonaligned countries, and that's what counts. The meeting serves as a sort of meter registering the political currents running through that very large part of the world that has neither great military nor industrial strength.

The worldwide distribution of wealth is not likely to come up except in the most rhetorical and unspecific of terms. The nonaligned countries used to be the poor, but recently things have become more complicated. Some of the world's richest countries are now the oil exporters that are members in good standing of the Third World. In Havana, any discussion of the world's wealth will have to be conducted with great tact to avoid splitting the sellers of oil from the buyers.

Nonalignment was originally a response to the Cold War, and to the aggressive bloc-building by the major powers. But the tone of international politics has changed since then, and perhaps even some of the delegates at Havana will find themselves wondering, privately, how much the nonaligned countries still have in common. The answer is that, at the least, they find in these meetings mutual support for their own ideas of independence. It's the definition of independence that's now at stake in the maneuvering between the Yugoslavs and the Cubans.