WHEN President Derek C. Bok told the Faculty in February that Harvard's free-speech policy should not deviate from the First Amendment, he implied that the University had a choice. It could choose to go the way of Michigan, Emory and Wisconsin and ban offensive speech or it could choose to sink or swim with the Constitution.

But does Harvard really have any choice? Can the University legally do anything it wants when it comes to rules about student speech?

THE answer may lie in the case of a Boston University student who had the misfortune of getting into a fight with the now-infamous John R. Silber. In 1986, Yusef Abramowitz lived in one of B.U.'s many student dormitories. Concerned about the university's South African holdings, he put a poster advocating divestment in his window.

To most, the "B.U. Divest" sign seemed innocuous. But not to Silber. Every time the loose-lipped administrator turned around to admire the view, the offending message called out to Silber like a blight on the landscape. Bruce Springsteen posters and foreign flags were one thing, but posters criticizing the university were quite another.

Never one to beat around the bush, Silber sent some goons over to take the sign down. Easy enough. It is a B.U. building, after all. But Abramowitz wasn't willing to take "no" for an answer. He proved that as fast as the functionaries could take the placards down, he could put another one up.

Silber was furious and ordered subordinates to notify Abramowitz that his housing contract would be terminated. The threat of expulsion from university housing was enough to bring the Civil Liberties Union of Massachusetts (CLUM) into the fray.

When the case came to court, CLUM relied on the Massachusetts Civil Rights Act. The law, unlike any other in the nation, prohibits any person from threatening, intimidating or coercing any other person in an attempt to interfere with the exercise of "rights secured by the Constitution or laws of the United States, or...of the Commonwealth" of Massachusetts.

Suffolk Superior Court Judge Haskell C. Freedman '30 ruled that B.U. had violated the law. The university's threat to expel Abramowitz was aimed at quashing his speech, Freedman said. The court imposed constitutional standards usually reserved for government agencies on an entirely private university.

Other Massachusetts courts have used the same law to restrict the rights of shopping mall owners and symphony orchestras to take action against people based on the nature of their speech. The message the courts have sent is that even if you own the property, you don't have an absolute right to control what is said there.

WHERE does all this leave Harvard? Somewhere in legal limbo. In any other state, a private college like Harvard would have significant leeway in determining what speech should be permitted and what should be punished. But, as people from one end of the political spectrum to the other have pointed out, Massachusetts is not quite like any other state.

The perfect test case would have been Tufts' harassment policy, which sliced the campus up into speech zones. In some areas, one could speak freely. In others, students could be punished for verbal, written or graphic speech which offended other members of the community. The certain legal battle was never realized because Tufts President Jean Mayer axed the new rules.

Harvard would like to think it could do anything Stanford, Yale or Cornell could, but when it comes to speech rules, it can't. Because of the Massachusetts Civil Rights Act, an antiharassment rule that might be entirely legal at Princeton might be impossible for Harvard officials to impose.

It is noble for Bok and the Faculty to have decided that they can't improve on the First Amendment. But everyone should realize that, for better or for worse, Harvard's policy in this area is much more a function of legal necessity than of academic choice.