July 3, 1981

Six warships of the North Atlantic alliance, their gliding silhouettes cleaving the choppy bay waters and the early morning mists, sailed into New York Harbor yesterday to signal the start of the city's 1981 Harbor Festival over the Fourth of July weekend. Led by its flagship, the Dutch guided-missile frigate De Ruyter, the fleet of frigates, known as Standing Naval Force Atlantic, brought more than 1,300 officers and crew members from six NATO nations to participate in the holiday festivities, which begin today and end Sunday. Mayor Koch greeted the commander of the fleet, Commodore Jan Jacob Leeflang of the Netherlands, with the key to the city. ''What a pleasure it is to welcome the Dutch back to New Amsterdam,'' he said, ''but we will not give it back.'' The Mayor also expressed hope that the sailors would enjoy ''a vigorous and enthusiastic'' stay.

The Greek Theater of New York is inaugurating its new home at 120 West 28th Street with a production of Sophocles' ''Elektra'' in modern Greek. It stars Anna Makrakis, a leading tragedian with the National Theater of Greece, who is also directing the production. The play, described by Miss Makrakis as a ''fierce tragedy where no murder takes place on stage and yet the smell of blood is ever present,'' is the post-Trojan War drama in which Electra prods her brother, Orestes, to avenge the slaying of their father, King Agamemnon, by their mother and her lover. Performances Tuesday through Saturday evenings at 8, matinees Saturday at 2 P.M., Sunday at 3, through July 19. Tickets are $10 ($6 for students and the elderly). Reservations: 869-3530.

A Criminal Court judge who let a woman charged with murder stay at his home for the night has been censured by the State Commission on Judicial Conduct for ''extraordinarily poor judgment and a serious misunderstanding of the role of a judge in our legal system.'' The commission declared, in an 8-to-1 ruling, that the actions last November by the Brooklyn judge, Alan I. Friess, had ''compromised the judge's impartiality in the case and diminished public confidence in the court.'' ''Though respondent was motivated by compassion for the defendant, the result of his conduct was to bring the judiciary into disrepute,'' the commission said in a written opinion.

The Supreme Court ruled unanimously today that Presidents Carter and Reagan had the legal authority to carry out the agreement with Iran that ended the hostage crisis. The Court acted on the final day of its 1980-81 term, only 17 days before more than $2 billion in Iranian assets are due to be transferred out of the country under the terms of the agreement. The ruling, in which all nine Justices took part, upheld the authority of the White House to nullify court orders and to suspend private lawsuits in order to honor the settlement. Associate Justice William H. Rehnquist emphasized several times in his 31-page opinion for the Court the narrowness of the ruling and its foundation in Congressional enactments and attitudes that have developed over many years, rather than on broad constitutional precepts. ''We do not decide,'' Justice Rehnquist said, ''that the President possesses plenary power to settle claims, even as against foreign governmental entities.''

Damage claims by workers exposed to asbestos and by their families now constitute the largest, and potentially most costly, block of product liability litigation ever to confront American industry. About 25,000 people who believe they are victims have already filed 12,000 suits against 260 companies that manufacture, use or sell asbestos products, according to Michael Mealey, editor of the Asbestos Litigation Reporter. More than 400 new suits are filed each month against the Johns-Manville Corporation of Denver, once the biggest asbestos producer, by those claiming injury from exposure. That is an increase from 150 a month last summer, and as of May Johns-Manville had been named in a total of 7,200 suits, many with several plaintiffs. ''It is impossible to predict when it will peak,'' Richard B. Von Wald, Johns-Mansville's corporate counsel, said of the cases faced by the company, Resolution of the cases holds broad implications for the liability of both manufacturing companies and their insurers and for the way that American industry deals with hazardous but economically valuable materials. Asbestos is one of the most widely used mineral products, as an insulator, a coating for cables and wires, and a component of floor and ceiling tiles.