I am very disturbed to see the flap over the Joe Biden video turn into a third "scandal" by comparisons of what happened to Gov. Michael Dukakis with what happened to Sen. Biden and former senator Gary Hart. Above all, it is disturbing to hear the words "dirty tricks" applied to what campaign manager John Sasso did.

Have people forgotten what dirty tricks were? That term was invented by President Nixon's 1972 campaign people to describe immoral, misleading and often illegal tactics. People went to jail for those dirty tricks! What Mr. Sasso did was to put together two videotapes to show that Sen. Biden had used not only someone else's words but someone else's family history. There was nothing misleading or dishonest in that clip. Was it embarrassing? Sure, but since when is that an unfair part of a campaign? The video was apparently not meant to, nor did it by itself, force Sen. Biden to withdraw.

If this action had been taken against a candidate of the opposite party, there would have been no complaint at all. It is thus only a question of intraparty politics.

There is only one point on which Mr. Sasso could be faulted by a Democrat: timing. Coming at the beginning of the hearings for Robert Bork, the action weakened the very person who was to lead the anti-Bork charge. But even here, had the clip been an isolated item, it would have played no role whatever.

It takes a great misunderstanding of both campaign strategy and political history to consider what Mr. Sasso did as fundamentally or ethically wrong. Perhaps he ought to have admitted immediately that he was responsible. But it is certainly understandable that he did not, once his tactic -- meant to be a minor annoyance to the Biden campaign -- turned out to lead to more truth than he might have suspected and to Sen. Biden's eventual withdrawal. For exactly the same reason, it is clear why he did not admit the truth even to Gov. Dukakis. Given what resulted, his resignation was unfortunate but necessary.

Most important at this moment is what this means politically for Gov. Dukakis. It has been said that the incident reflects badly on his leadership abilities and his skill at keeping his people "under control." Neither Mr. Sasso's action nor his failure to tell the governor should reflect in any way on Gov. Dukakis.

This story is in no way similar to the Hart and Biden stories, each of which revealed personality flaws that reflected seriously on their possible future conduct as president.

JOEL M. COHEN Washington

Before we cripple Michael Dukakis' bid for the White House, let's put the John Sasso incident in perspective. Mr. Sasso did a service by exposing Joseph Biden as a plagiarist. If Mr. Sasso had publicly shared the Biden tape, the public might have increased its respect for Gov. Dukakis.

The incident shows that Gov. Dukakis did not know of every action his staff took. Realizing that people will judge his integrity by that of those who work for him, Dukakis had the guts to let his No. 1 aide go.

DAVE WEST Bethesda