"Casey Details Secret Soviet-Cuban Strategy," the banner headline trumpeted on page one of The Washington Times. "Casey" is William Casey, the boss of the CIA. The story predicted breathlessly that on the very next day he would give to a meeting of the World Business Council in San Antonio, "the most comprehensive argument for U.S. assistance to the Nicaraguan resistance yet put forward by the Reagan administration."

Casey's remarks in San Antonio were actually "off the record." What the Times was heralding on the supposed eve of delivery was a speech the CIA says had been delivered -- on the record -- on May 1 to the Metropolitan Club of New York. It went unnoticed for more than two weeks, until somebody obligingly called it to the attention of the Times, which says something about the market for the administration's case.

But the speech itself says something of greater concern about the inner workings of the administration's collective mind. It says that the Soviet Union as the "focus of all evil" is not just the president's figure of speech. It is an ideological concept, imbedded in the most sacrosanct branch of the national security bureaucracy, and in the person of the director of Central Intelligence whose measured analyses and assessments are supposed to be the reinforcing rods of policy.

So you may judge for yourself, here are some excerpts from Casey's presentation. Note the even tone and balance; the absence of any hint of hysteria; the reverence for facts and figures; the fine logic of his approach.

The Soviet Union's "subversive war" against U.S. interests over the past quarter of a century is neither "undeclared" nor "bloodless." Nikita Khrushchev warned us and we didn't listen.Now look: "Marxist-Leninist policies and tactics" have unleashed the four horsemen of the apocalypse. "Throughout the Third World we see famine in Africa, pestilence through chemical and biological agents in Afghanistan and Indochina, war on three continents, and death everywhere.

"In the occupied countries -- Afghanistan, Cambodia, Ethiopia, Angola, Nicaragua -- in which Marxist regimes have been either imposed or maintained by external force . . . has occurred a holocaust comparable to that which Nazi Germany inflicted in Europe some 40 years ago."

Getting down to the Nicaraguan case, Casey says "the Soviet Union and Cuba have established and are consolidating a beachhead on the American continent . . . and have begun to use it as a launching pad to carry their style of aggressive subversion into the rest of Central America and elsewhere in Latin America. . . . The Sandinistas have developed the best-equipped military in the region. . . . Nicaragua could walk through Costa Rica, which has no army, to Panama, and can threaten our vital sea lanes in the Caribbean."

The Sandinistas have already satisfied 33 of the 46 "indications of the consolidation of power by a Marxist-Leninist regime," as defined by CIA analysts. Among those already accomplished: control of the media; censorship of the press and religion; control of the education system, the military and the internal secret police. "There are Soviet advisers at every level of the secret police," Casey reports. "Block committees have been established to watch and control the people."

How a counterrevolutionary effort at anything like the present or projected levels could displace this Sandinista powerhouse, Casey doesn't say. But his aim is steady. Regional negotiations would buy time for the Sandinistas to consolidate their hold. Agreements designed to contain Nicaraguan adventurism are valueless "unless Nicaragua has implemented a genuine democracy." For one thing, they could not be verified; for another, history shows the communists don't keep their word. "As long as the Sandinista regime in Nicaragua remains, that country will serve as a base for communist expansion in the area," Casey concludes.

So there you have it, and never mind that President Reagan, cajoling Congress for "contra" aid money last week, was singing a different tune -- "We do not seek the military overthrow of the Sandinista government."

The Casey definition of the Nicaraguan threat to U.S. vital interests leaves room for no other U.S. objective -- and no other final outcome.