Cuban involvement in El Salvador's civil war is now established beyond any doubt. And the Reagan administration's carefully orchestrated diplomatic offensive to convince Western Europe and Latin America of the Cuban role is yielding results.
Although most of Latin America counsels Washington to keep US troops out of the struggle, the hemisphere is increasingly sympathetic to sharply stepped-up US military assistance to the embattled military-civilian government in San Salvador.
A number of governments are looking seriously at their own diplomatic relations with Havana. It is known, for instance, that several countries have considered pulling out their ambassadors in protest over the Cuban shipment of arms to Salvadoran guerillas. And Cuban embassies in Latin America have been told of their host governments' displeasure over the Cuban role in El Salvador.
All this comes as Washington releases its "white paper" on the Cuban role, which outlines "the direct Cuban involvement."
The US makes these points:
* The political direction, organization, and arming of the Salvadoran insurgents are coordinated and strongly influenced by Cuba, with the active assistance of the Soviet Union, East Germany, and Vietnam.
* Cuba has also served as a major collector of arms for the Salvadoran guerillas -- shipping at least 200 tons of weapons, ammunition, and military devices during the past 18 months and promising more than 600 additional tons.
* In contrast, from 1977 to January of 1981, the United States did not supply arms or ammunition to the Salvadoran government, and limited US military aid, resumed in 1980, was nonlethal equipment.
[In January, 1981, former President Jimmy Carter authorized $5 millin additional military assisance for combat equipment, including rifles, ammunition , and grenade launchers.]
* The Salvadoran rebels and the Cubans have done all they could to mask the arms flow and to give the guerilla cause a non- Marxist political orientation that they hoped would -- and did -- encourage support of the guerillas by some Latin American governments.