I was astounded by Randall Kennedy's defense of the protesters who disrupted the speech of a South African official at Harvard earlier this year {op-ed, June 27}. That a professor of law at one of our nation's finest institutions believes suppression of speech is a legitimate form of political action bodes ill for democracy.

Prof. Kennedy correctly points out that there are conditions under which a person's right to free speech can be limited. However, holding opinions which some happen to find offensive or with which some happen to disagree has never been considered such a condition. Prof. Kennedy's two justifications for suppressing freedom of speech in such circumstances are weak at best.

First, he says the demonstrators had a "legitimate interest in preventing South Africa from advancing its ideological war against racial justice." True, but so what? Everyone has a legitimate interest in advancing his political opinions, but everyone also has a responsibility to use legitimate means. If our democracy is to function, suppression of another person's rights cannot be considered legitimate political action.

Second, he says an official of the government of South Africa should not be allowed free speech because that government does not respect its citizens' right to speak. Using this criteria, students could assault or shout down officials from most of the world's countries. Neither education nor understanding would be advanced by such a situation.

Implicit in Prof. Kennedy's column is the idea that the denial of free speech to a South African official is unimportant because the official probably didn't have anything worthwhile to say. Having heard Duke Kent-Brown speak, I know this presumption is not true. Though I was hardly convinced by him, I learned much more about the opinions and stances of the South African government from him than I have from the media's superficial coverage.

If history has taught us anything, it is that democracy can only survive if there is a respect by every citizen for the rights of all citizens. Unfortunately, Prof. Kennedy and the demonstrators at Harvard have yet to learn this lesson. PETER S. HEINECKE Washington