October 23, 1982

Twenty years ago today, President John F. Kennedy publicly demanded that the Soviet Union remove its missiles from Cuba or else. And for 13 days, until agreement on their removal was reached, he thought that the chances of nuclear war were 1 in 3 or even. ''Above all, the Cuban missile crisis is a vivid reminder that, unless the superpowers act very carefully, they can set off a chain reaction leading to nuclear war,'' Graham T. Allison, dean of the John F. Kennedy School of Government at Harvard, remarked recently. For 20 years, the middle course charted by Mr. Kennedy to bring about the withdrawal of the missiles - neither direct military attack nor words alone - has served as a model to his successors on how to handle crises. At the time, this middle way was generally judged a brilliant success.

More gains were announced today for the political arm of the outlawed Provisional Irish Republican Army in Wednesday's elections in Northern Ireland, causing widespread private expressions of dismay among officials in London. Tabulation of the votes, while not yet complete, showed that the I.R.A.'s political organization, Sinn Fein, had picked up two more seats, for a total of five, in the 78-member assembly. This showing was widely regarded as an important psychological victory for the party, which entered 12 candidates, all in urban areas where Roman Catholics are concentrated, and campaigned on a slogan of ''A ballot in one hand and a gun in the other.''

The Essex County Prosecutor said today that he would move for dismissal of a misconduct charge against Mayor Kenneth A. Gibson. He had been accused of creating a ''no show'' job for a former City Councilman. On Thursday, a Superior Court judge declared a mistrial on the charge after a jury failed to reach a verdict. The jury acquitted Mr. Gibson of a conspiracy charge in connection with the job for the former Councilman.

A judge today ordered a hospital to discontinue life-sustaining treatments for a 41-year-old diabetic at his request, and within an hour the man died. The man, Peter Cinque of Lynbrook, died in the intensive-care unit of Lydia E. Hall Hospital in Freeport, L.I., at about 5 P.M. In his order, Justice Arthur D. Spatt of State Supreme Court had directed Mr. Cinque's doctors to honor his request to halt his dialysis treatments. ''In this state, there is no statute prohibiting a patient from declining medical treatment or a doctor from honoring a patient's decision,'' Justice Spatt said. ''The court finds Peter's decision was based on a compelling desire to escape the grievous pain and suffering.''

King Hassan II of Morocco met with President Reagan today and said that ''peace and coexistence'' in the Middle East could be achieved on the basis of American and Arab proposals and United Nations Security Council resolutions. The King, the leader of an Arab League delegation, did not specifically define what he meant by ''coexistence,'' or mention Israel. But a senior State Department official said later that the King's choice of words was important. In the private discussions, the official said, ''it was well understood that we were talking about a state called Israel and peace negotiations, the terms, modalities for negotiations.''