The Supreme Court has played different roles in the history of our country. Sometimes it has been a passive branch, resolving mostly private disputes and letting the political branches make and change public policy. Most of the time it has tried to avoid the "political thicket."

In 2000, however, it inserted itself into the granddaddy of all political disputes when it decided that Florida's electoral votes would be awarded to George Bush. While Bush v. Gore was an obvious attention-grabber, there have been others in which the current court has flexed its political muscles:

* It has imposed limits on what areas Congress can regulate.

* It has cut back substantially on any affirmative action programs that government agencies can conduct, even when legislatively authorized.

* And doubt continues to fester on whether the Constitution guarantees a woman's right to terminate a pregnancy.

What makes these court decisions so troublesome, albeit fascinating, is that most have been resolved 5 to 4. With three justices over age 70, speculation about a change in the court's delicate balance is unavoidable. What kind of person would President Bush nominate? And what kind of nominee would the Senate confirm? Suppose the Senate did not confirm anybody. Would that be deemed political conduct? Would that be a responsible exercise of the Senate's constitutional power? I think the answer to both questions is yes.

There is nothing magic about the number nine for the size of the Supreme Court. The Constitution does not suggest a number, and the first court was authorized to have six members. The authorized number has gone up and down during our history, usually for very political reasons. It went to 10 in 1863 and then was reduced to nine because Congress was angry at President Andrew Johnson. In the 1930s when the court continued to strike down New Deal legislation, President Franklin D. Roosevelt threatened to increase the size of the court by one for every justice who was over age 70. The plan failed in passage, but "apostasy and death" caused the court to reverse its doctrinal direction.

Vacancies also have persisted when the Senate was unhappy with the particular nominee that the president sent up for confirmation. While sometimes the retiring justice has continued to serve until a successor was chosen, often the resignation was immediate or the vacancy occurred as a result of death. For example, a vacancy existed for three years because Congress was unhappy with President Lincoln's choices, and then with those of his successor. When Congress was unhappy with Lyndon B. Johnson's effort to promote Abe Fortas to chief justice, a vacancy persisted for more than a year.

The Constitution states that the president is to nominate justices and appoint them "by and with the advice and consent" of the Senate. While presidents seldom request the advice of the Senate in advance of their nominations, it has occurred. President Hoover wanted to appoint a westerner to fill a vacancy, but his ally, Sen. William Borah of Idaho, persuaded him to appoint Justice Benjamin Cardozo instead. President Clinton was discouraged from nominating Sen. George Mitchell at least in part by senators who thought it would be a political mistake.

There are more than a few occasions in which the Senate has exercised its political powers to help shape the makeup of the court. There are special reasons why the present political climate warrants such an action.

First, this president does not have the mandate of a national plurality. While the court did resolve the dispute about Florida's electoral votes, giving President Bush an electoral college majority, it could not alter the popular vote. Bush lost to Al Gore by more than 500,000 votes. Most of the other appointments the president will make are for finite terms, but his choice to fill a vacancy on the court -- a lifetime appointment -- probably would serve for many years after the people resolve this political anomaly and elect a president who wins the popular vote.

Second, the delicate balance of the court on fundamental issues makes even a single appointment of great moment. During the Warren Court years, when the justices made some fundamental changes in criminal justice, elections and the system of segregation in our public institutions, there were usually substantial majorities supporting the result. The Warren Court did not strike down that many congressional decisions. But seldom in its history has the court invalidated so many acts of Congress by 5 to 4 decisions as at present.

Still another reason that the political climate warrants Senate involvement is that the court itself made the final decision as to who should be president. That judgment raised many doubts about the legitimacy of the court's actions. There was gossip that at least one of the justices was upset by the consequences to the court of a Gore victory, and that one of the justices in the 5 to 4 majority was close to changing his vote. Conservative scholars who favored the result of the case politically have nevertheless criticized the "equal protection" rationale the unsigned majority opinion provided for the decision. While the events of Sept. 11 have stilled much of the controversy about the manner in which the 2000 election was decided, there is still unhappiness, partisan and otherwise, about the court's intervention.

The appointment of Supreme Court justices is a shared responsibility. The Senate has a plenary power to advise and consent. This has never been perceived to be some kind of rubber-stamp function, and it has been used with substantive results on less compelling occasions.

This Supreme Court is in an activist mood. Each year yields a bumper crop of decisions that overrule or modify political choices made by Congress. If there are to be changes in its personnel, they ought to be made by a president who has a popular vote mandate. I think the Senate should not act on any Supreme Court vacancies that might occur until after the next presidential election. Changes in the existing delicate balance could put the very legitimacy of the court as an institution at risk. Other than the black robes and the high bench, that legitimacy is all that the court has going for it.

The writer has served as a Democratic House member from Illinois, as chief judge of the U.S. Court of Appeals for the D.C. Circuit and as White House counsel under President Clinton. He is currently a visiting professor at the University of Chicago Law School.