The best kept secrets in the nation's capital these days are the views of Supreme Court nominee Anthony Kennedy on the great constitutional rights issues that will be coming before the court in the months and years ahead. The Senate Judiciary Committee hearings last month amounted to little more than a game of blindman's buff with the nominee. What made the committee's failure to get at Judge Kennedy's views on the Bill of Rights all the more incomprehensible is that it came right on the heels of the committee's determined effort to flush out every detail of Robert Bork's thought process in the area of constitutional rights. If Judge Bork hadn't taken so narrow a view of the reach of the Fifth and 14th amendments, he might be in the courts himself right now suing for "equal protection of the laws."

But the question whether Judge Kennedy should be confirmed in hasty ignorance of his views is too important to be laughed away. The Supreme Court is split 4 to 4 on such vital constitutional issues as separation of church and state, school prayer, abortion, affirmative action, school integration and other civil rights enforcement matters. Kennedy will be the swing vote in this area for years to come, and confirmation without knowing his views on these issues is a reckless course for Senate guardians of the Constitution.

It is not too late for the Senate committee to do its job. The committee hearings should be reopened and Judge Kennedy recalled. A delay of a month or two in the confirmation process is minimal compared to the quarter of a century Judge Kennedy will likely serve on the court if he is confirmed.

This is not to suggest that Kennedy be recalled to testify about how he will rule when these great issues come before the court. Of course not. But what the committee does have the right to do -- no, the duty -- is to search out the views Kennedy expressed when the Supreme Court decisions now under attack were decided, and base its collective judgment on those views.

Kennedy has been a professor of constitutional law for 23 years. He has been a member of a court involved with constitutional law for 13 years. Obviously he expressed his views on vital Supreme Court decisions to his faculty, student and judicial associates as the decisions came down and remained under public discussion. What Kennedy said about these decisions are facts for the Senate to consider just as what Judge Bork wrote about the decisions were facts that the Senate did consider only a few months ago. Yet, surprising as it may seem, no member of the committee asked Kennedy what he said to his associates on those occasions.

Reopened hearings could serve a second purpose. For seven years the Reagan administration has sought by constitutional amendments, statutes and court decisions to roll back the great advances in civil freedom of the last quarter-century. These efforts have largely failed. The Powell replacement on the Supreme Court is the administration's last chance to accomplish its goal of a constitutional rollback. Bork and Douglas Ginsburg were the first two forays at that goal. It is inconceivable that the administration made its third nomination without some clear idea, from the nominee or third parties, of his views on the decisions they seek to reverse. The committee, the Senate, the media and the public have a right to know what the administration knows on that score. The efforts of the committee to get at this information were halfhearted, hasty and never followed up. It's not too late to remedy this, too.

The reopening of the hearings is particularly necessary in this instance because the few cases in which Judge Kennedy participated involving significant civil rights issues showed a lack of concern for constitutional claims. Thus he opposed effective voting rights for Mexican Americans in the San Fernando case; opposed school integration in the Pasadena case; opposed standing for "testers" to sue housing discriminators; opposed equal wages for jobs predominantly performed by women; supported weight limitations for airline hostesses; supported the Navy's ban on homosexuals. Worse yet, and a frightening portent of things to come, Kennedy reached out for technicalities and ignored lower court findings in these and other cases where significant rights claims were at stake.

The principle involved in the Bork rejection was simple: the Senate, reflecting the public mood, did not want to see the constitutional issues of the last quarter-century refought. At best the present record on Judge Kennedy is inadequate to determine whether his addition to the crucially divided court will mean the very refighting of the issues the national consensus wanted settled; at worst the record indicates a probability in that direction. Whether by ignorance of the nominee's views or indifference to the result, the "Bork principle" is endangered at its first test.

One gets a little tired of the argument that Judge Kennedy is as good as the Reagan administration is likely to produce. If the Senate sends a message that it will confirm only a nominee with a proven record of support for the Bill of Rights, the new "pragmatic" White House of arms control, increased taxes and lowered rhetoric can be expected to find a nominee who does not threaten the "Bork principle." At a time when we are pressing other countries on human rights, retreat at home should be unthinkable. The writer is a Washington lawyer long active in civil rights causes.