March 18, 1984

F OR almost two weeks, Gary Hart remained silent under Walter F. Mondale's repeated suggestions that Americans should not entrust the Presidency to a man as unknown, untested and perhaps unstable as Mr. Hart. Finally, on Thursday, Mr. Hart struck. ''He knows in his heart there is no blemish on my character that would prohibit me from governing this country in this decade,'' Mr. Hart said. Later that day, the Colorado Senator backtracked, saying he had been incorrectly told that the former Vice President was running commercials about the fact that Mr. Hart has changed his name, his date of birth and his signature. The curious incident underscored the extent to which the race for the Democratic Presidential nomination has become a contest in which the candidates' liabilities may be more important than their strengths. Strategists on both sides are bracing for a clash of negatives. Does Mr. Mondale, despite being propped up by endorsements and a seasoned staff, suffer from a chronic inability to stir the American people? Do the quirks in Mr. Hart's biography signify deeper problems of character and personality? That is what the candidates themselves are suggesting, as they exchange denigrations in what is, following last Tuesday's voting in 11 primaries and caucuses, more clearly a two-man race.

The republican terrorist who headed Ireland's most-wanted list was captured today after a shoot-out at dawn with 40 heavily armed detectives at an isolated cottage in the Irish Republic where he was holed up with three confederates. The St. Patrick's Day seizure of the terrorist, Dominic McGlinchey, known as Mad Dog because of his ruthlessness, came after a 90-minute gun battle during which one of the policemen was wounded in the shoulder. His apprehension was hailed by James Prior, Britain's Secretary of State for Northern Ireland, as a major victory in the struggle against terrorism. John Taylor, Northern Ireland's representative in the European Parliament, said that ''in the midst of all the meaningless rhetoric which we suffer from on this, our national day, this is the best news to come out of Dublin for many years.''

With 6 minutes 51 seconds remaining in the opening quarter last night, Bernard King was called for a rare foul: He was caught throwing an elbow at Mark Olberding. At the time of the call, King had scored only 2 points. The elbow the Knick captain threw was in retaliation for some rough treatment under the boards, and the incident seemed to make him more determined. King went on to score 36 more points that paved the way for a 123-109 victory over the Kansas City Kings at Madison Square Garden.

NEW HAVEN WHEN Yale's School of Organization and Management opened its doors in September 1976, Kingman Brewster Jr., then the university's president, presented it with its own coat of arms. The shield's abstract design depicted two conference tables - one gold, one silver - surrounded by dots of gold and silver. At the bottom was the motto ''Novus Ordo Seclorum'' - ''A New Order for the Ages.'' Yale's was not to be just another business school. This was to be a place where leaders would be trained for both the public and the private sectors - the gold and the silver - a place where the interaction of government and business would be stressed.

NEW ROCHELLE WILDCLIFF MUSEUM, once one of this city's premiere resources, attracting thousands of patrons yearly from the county and beyond, is about to be resurrected - not as a nature center, its original incarnation, but as an arts institution that will include a 150-seat theater. Last Tuesday night, by a vote of 4 to 1, the New Rochelle City Council approved a plan that would permit a nonprofit group, East Coast Arts, to convert the museum and to present such offerings as plays, readings, operas, concerts and dance programs. An art gallery will also be created.