THE ADMINISTRATION-proposed Radio Marti, which would broadcast news of Cuba to Cubans, faces an evident do-or-die mark-up session in the Senate Foreign Relations Committee; it has already been approved in the House. For lack of an enthusiastic champion in the committee, the station could conceivably succumb to the prevalent atmosphere of doubt. This would be, we think, regrettable. An effective Radio Marti could be of value to American foreign policy.

The principal doubt about the station is that it represents a hard, intrusive line when the real need is for a moderate negotiating line. But broadcasts are not inconsistent with negotiations. Why not conduct both? Anyway, there need be no apology for a hard line if by that is meant offering Cubans an American-style alternative to the material put before them by their government-controlled media -- as Radio Free Europe and Radio Liberty do for East Europe and the Soviet Union. Certainly, open broadcasts are a more acceptable expression of administration hostility to Fidel Castro than, say, another Bay of Pigs. In this administration there is undeniably a danger of the broadcasts' becoming propaganda broadsides; the experience with RFE and RL and the certainty of failing to gain or keep an audience constitute the best guarantees against such a turn.

The second area of doubt about Radio Marti concerns Cuban radio interference with domestic broadcasts in the United States and other countries of the hemisphere. The Cubans are threatening to step up the number and power of their international broadcasts if Radio Marti goes on the air. But wait a minute: Cuba is a mouse of a country with, already, an elephant's radio roar. Its radio interference and its refusal to be a good neighbor of the air waves long predated the announcement of Radio Marti. The latest Cuban threats recycle familiar and ambitious international broadcast proposals that Havana may or may not have the resources to deliver on. The correct response for the United States is to keep on insisting, with similarly aggrieved Latins, that Cuba accept the standard procedures for working out disputes over radio broadcasts.

The administration has misadvertised and oversold Radio Marti as something like the beginning of the end for Fidel Castro. That's foolish. It is enough that it is a modest and potentially useful step to make available to interested Cubans a flow of information and opinion that Americans have routinely provided to other communist-controlled countries for decades and that Americans rightly take for granted for themselves.