As predicted, the Senate hearings to determine whether Judge Robert Bork should get a seat on the U.S. Supreme Court will run from controversial to downright nasty. Political partisanship and conflicts of ideology will run through the hearings like a muddy river.

But don't swallow the line that such hearings are ''unprecedented'' or simply a ''witch hunt'' carried out by a bunch of liberals. Some of the people fighting hardest to get Bork confirmed have themselves used political and ideological tests -- and the filibuster -- to block court nominees they did not like.

When Lyndon Johnson nominated ''liberal'' Abe Fortas to become chief justice, Sen. Strom Thurmond (R-S.C.) told senators: ''To contend that we must merely satisfy ourselves that Justice Fortas is a good lawyer and a man of good character is to hold to a very narrow view of the role of the Senate, a view which neither the Constitution itself nor history and precedent have prescribed.''

Clearly, this Senate is not going to rubber-stamp the Bork nomination simply because he has taught law, has other academic qualifications and is not guilty of moral turpitude. More is at stake in the Bork nomination than was the case with Fortas, which is why Bork is looked at with suspicion, even fear, by millions of Americans.

Some conservative southerners of strong religious devotion want their senators to determine whether Bork is ''an agnostic.''

Millions of women are asking whether this appeals court jurist believes they have any rights to make decisions about reproduction under the Constitution. Does Bork really think the state is empowered to tell a woman she must carry a baby to term or tell a couple they may not (or must) use contraceptives?

Many blacks are eager to learn whether Bork still believes that it is unconstitutional to tell the owner of a restaurant he cannot refuse to accept minority customers. Blacks, like millions of other Americans, want to know whether Bork ever saw a civil rights law he liked and would approve.

Newspaper and TV people, university scholars, book authors and others are -- and should be -- shaken by Bork's 1979 comment that, in saying ''offensive'' language may be constitutionally protected, Justice Oliver Wendell Holmes showed ''a strange solicitude for subversive speech.'' Bork has never come across as a great friend of a free press.

Other Americans fear Bork has a warped and dangerously restrictive view of how much power the Supreme Court should have to interpret things like ''due process of law'' and the rights to privacy.

Rights and issues vital to every American are at stake in this hearing, so this is no time for senators to ask perfunctory questions and then cave in before White House demands for confirmation.

If ''the real Bork'' turns out to be anything like the one who has been writing and talking all these years, the Senate must have the guts to vote him down.