ACCORDING to the back files of the International Institute for Strategic Studies (IISS), there were 200 Cuban soldiers deployed in Nicaragua in 1981 when Ronald Reagan came to Washington and took over American foreign policy. The number went to 1,000 in 1983 and then to 3,000 in 1984. The latest edition of the annual IISS report on ``The Military Balance'' again carries the figure of 3,000.
In other words, the presence of Cuban troops in Nicaragua in support of the present Sandinista government of Nicaragua is not new. But it climbed as the Reagan administration in Washington organized and deployed a counterrevolutionary force against that Sandinista government in Nicaragua.
There was a flurry of excitement in Washington last week over those Cuban troops in Nicaragua. United States Assistant Secretary of State Elliott Abrams, testifying before a congressional committee on Dec. 5, said that the Cubans were, and had been for some time, taking part in combat. Surprisingly, he used the figure of 2,500 for Cubans in Nicaragua. Normally in such matters, United States government officials use the highest figure available, particularly when they want more money from Congress.
The flurry of renewed interest in the story of the United States vs. Nicaragua had started earlier in the week, on Monday, Dec. 2, when the US-backed rebels, or ``contras,'' successfully shot down a Soviet-built helicopter. The contras used a Soviet-built SA-7 guided missile for the shooting.
The Soviet SA-7 is a lightweight hand-held antiaircraft weapon. It has been deployed for over 10 years. It is widely used in the armed forces of the Soviet Union and its clients worldwide. Apparently it can be bought on the open market. The story offered in Washington of how the contras obtained a Soviet-built SA-7 is that it was probably bought in Portugal.
The use of the SA-7 by the contras was apparently a shock to the Nicaraguans. Nicaraguan President Daniel Ortega Saavedra promptly denounced it as an act of ``escalation.''
That takes us back a ways. There has been steady escalation in and around Nicaragua for some time. It began with the 1981 decision of the Reagan administration to organize and mount an anti-Sandinista force. Deployment of that force in Honduras began in 1982. It reached its peak of effectiveness in midsummer of 1984. At that time, contra raids penetrated within some 40 miles of the capital.
That phase of contra activity had been made possible by light planes capable of supplying the rebels well inside Nicaragua. They could, with supply by air, stay ``inside'' for days, even weeks at a time. But in war there is often a new answer to a new move.
The United States supplied the supply planes to the contras. The Soviets responded by sending helicopter gunships to the Sandinistas. Those gunships put the contras into a winter lull. Their supply planes fell easy victim to the Sandinista gunships. The contras have had a quiet season in which to regroup.
They were revived when Congress reluctantly authorized $27 million for ``humanitarian'' help. How ``humanitarian'' help got translated into Soviet SA-7 weapons is a story that lies hidden in that realm of action called covert in the current jargon of Washington. But obviously the SA-7s are an answer to the gunships.
So there has been steady escalation back and forth ever since 1982. The United States built the contra force. The Cubans sent 3,000 soldiers to help the Nicaraguans. The United States provided the contras with the capability of supply by air. The Soviets answered with gunships. The contras got SA-7s.
Where does it lead? US Secretary of State George P. Shultz has gone off on a trip to Europe, leaving behind a hint that he might come back and ask Congress to provide overt United States military aid to the contras on the ground that the Cubans have escalated their role by going into combat with the Nicaraguans.
It begins to look as though the Sandinista regime in Nicaragua can be brought down only by actual overt use of US troops. So long as United States aid is supposedly ``clandestine'' and ``covert,'' it is possible for Moscow and Havana to countermove by a new move.
At some point, Mr. Reagan will probably either have to give up in Nicaragua or send in the United States Marines, plus a big chunk of the United States Army. The Sandinistas now have about 60,000 men under arms, with steadily improving training and equipment.