The chief justice of the United States is the leader of the third branch of our government and has an enormous impact on the court and the nation. Now that Judge John G. Roberts Jr. has been nominated to fill this seat, the Senate and the American people need to learn far more about how he would lead our courts so we can evaluate whether he is the right candidate.

We need to determine whether he will help generate consensus and find compromise over hotly debated issues, or whether his decisions will further inflame political passions. The chief justice should represent all Americans -- men and women of all races and creeds, rich and poor, weak and powerful, Democrats and Republicans, religious and secular, young and old.

At the Judiciary Committee meeting this week, Judge Roberts should respond fully to questions about some of the most critical issues facing our nation. It would be a serious mistake to stonewall the committee members.

In the new term, the court will hear cases concerning parental notification about abortion, anti-trust, public education, bankruptcy, whistle-blower protections, and end-of-life decisions -- just to name a few.

Many other important issues are just over the horizon, including rights of enemy combatants; the scope of women's reproductive rights; and the extent to which Congress has the authority to protect our nation's environment through legislation. The new chief justice will play a pivotal role in directing the court and in determining the outcome of these and other future cases.

Chief Justice William Rehnquist will be remembered for a legacy defined by actively challenging the role of Congress. In recent years as the court has adopted a conservative ''states' rights'' view of several constitutional provisions, congressional authority to enact important legislation has been significantly curtailed.

This has occurred through its interpretation of the spending clause, the commerce clause, the 14th Amendment, and the 11th Amendment.

Based on these federalism grounds, the court has wiped out all or key parts of legislation addressing issues such as religious freedom, overtime protections, age discrimination, violence against women, discrimination against people with disabilities, and gun-free schools.

In fact, over the past decade, the Rehnquist court has weakened or invalidated more than three dozen federal statutes. Almost a third of these decisions were based on the commerce clause and the 14th Amendment.

If Judge Roberts subscribes to these interpretations of the law and the Constitution, the impact could lead to disarming Congress of its essential powers to tackle nationwide issues that the American people have elected us to address.

As the only woman on the committee, I believe I have an additional role in considering Supreme Court nominations.

I was elected in the wake of the Clarence Thomas hearings, when women of both political parties were angered by how the issues of sexual harassment and privacy were dismissed by some members of the all-male Judiciary Committee.

And for me, one of the most important issues that needs to be addressed by Judge Roberts is the constitutional right to privacy. I am concerned by a recent trend on the court to limit this right and curtail women's autonomy. It would be very difficult for me to vote to confirm someone to the Supreme Court who I know would overturn Roe vs. Wade.

From the founding of our nation, women have had to fight for every right we now enjoy. We were unable to own property, we were not allowed to vote, we had limited inheritance rights, and most women were not allowed to enter the workforce. And I remember what it was like when abortion was illegal.

I knew a woman who ended her life because she was pregnant. And in the 1960s, as a member of the California Women's Board of Terms and Parole, I sentenced women convicted of performing an illegal abortion. I don't want to go back to those days.

Whether the court upholds the right to privacy that has been settled law for more than three decades will affect both beginning-of-life and the end-of-life decisions; and whether these decisions remain private, or could be subject to government intrusion or perhaps the risk of prison.

When entering the Supreme Court, one looks up and sees on this enormous and impressive courthouse two inscriptions. They read ''Equal Justice Under the Law,'' and ''Justice the Guardian of Liberty.'' These are the standards.

The American people must decide whether Judge Roberts is prepared to uphold them.