AFTER American forces swept into Grenada in 1983, they unearthed a treasure-trove of documents detailing the secret relationship between the toppled Marxist regime and the communist bloc. These included a number of treaties that provided - secretly - for a military buildup in Grenada out of all proportion to Grenada's internal needs. Also discovered were notes of a meeting earlier that year between Grenada's Army chief of staff, Einstein Louison, and the Soviets' then top military man, Marshal Nikolai Ogarkov. Marshal Ogarkov talked of earlier hard times for the Soviet Union in Central America, when ``there was only Cuba.'' But then he went on to list approvingly Nicaragua, Grenada, and El Salvador as new outposts of Soviet influence and bases for spreading it further.
Well surprise, surprise, here is the Grenadian scenario being reenacted all over again in Nicaragua. Even as the Sandinista leaders proclaim peace and goodwill, they have been negotiating secret accords with the USSR for a major military buildup.
Details of the plan have been revealed by Maj. Roger Miranda Bengoechea, a close aide of the top Sandinista leaders who defected to the United States in October. There are a couple of reasonable question marks about what he has been saying, and the timing of his saying it.
Is he telling the truth? The United States has been burned before with defectors from Central America. This time, intelligence experts say they have walked all around this source and on balance he checks out. Some of his data have been confirmed by the Sandinistas themselves. And he has provided written documentation of his more significant charges.
Has he been surfaced by the administration at a time when his story would influence a favorable congressional vote on aid to the Nicaraguan contras? Administration officials deny this, but his account does not hurt the administration's campaign. The fact is that the Sandinistas admit the principal thrust of his charges - that they have been planning with the USSR, through Cuba, a major military buildup.
Major Miranda brought with him copies of two Nicaraguan-Soviet military accords. The secret agreements call for a major military buildup over the next seven years. They envisage a Nicaraguan military force of more than 500,000 full- and part-time soldiers. They provide for the delivery of MIG-21 jets - high-performance aircraft that the US has warned it will not permit in Nicaragua.
The detail the former aide has provided has sent the Sandinistas into embarrassing confusion. First the defense minister, Humberto Ortega Saavedra, confirmed the plans for a military buildup, stating defiantly that it was Nicaragua's ``right, whether Mr. Reagan likes it or not.'' Then his brother, President Daniel Ortega Saavedra, said the plan was merely a military proposal that had not been accepted. Then he hardened that position, saying Nicaragua would indeed maintain a military force of ``600,000 or more men'' in the Army and reserve even if it ``normalized'' relations with the US and its neighbors.
The enthusiasm for funneling manpower to the military should come as no surprise. Earlier this month the Sandinistas launched a new campaign to lure children into the militarized Sandinista youth organization. Children under 13 who failed the seventh grade of school this year can wipe out the failing grade by joining. That is expected to attract many youngsters whose grades were poor.
The revelations continue to cast doubt upon Sandinista protestations of their desire for peace in the region and democracy at home. They also leave unanswered the question of what Moscow will, or will not, do to curb the Sandinistas' military ambitions.