Before entrusting Judge John G. Roberts with a lifetime position on the Supreme Court, the Senate must be able to determine whether he will uphold the fundamental principles of our Constitution and laws to continue our nation's march of progress or whether he will adopt a cramped and contorted view of our Constitution that will turn back the clock.

To help us perform our constitutional duty, the Democrats on the Senate Judiciary Committee have requested information on 16 of the cases that Roberts handled as deputy solicitor general from 1989 to 1993. The information in those cases relates directly to his personal views on -- and his views on the courts' role in enforcing -- civil rights, disability rights, women's rights and other fundamental rights guaranteed by laws and the Constitution.

As deputy solicitor general -- the No. 2 job in the office that represents the United States in Supreme Court and other federal cases -- Roberts represented all the people of the United States, and the people are entitled to access his records from that time. The White House knows his positions, yet it continues to withhold documents that would help us understand his views of key fundamental rights and freedoms.

In an attempt to justify its refusal, the administration relies on a letter written by previous solicitors general in a different context concerning the public release of memoranda written by career lawyers in that office. On its face, the letter does not apply to memoranda written by Roberts. Indeed, as Walter Dellinger, a former acting solicitor general and one of the signatories of that letter, recently stated, "Roberts was writing memos not as a civil service lawyer but as a senior political appointee in a policymaking position, and the judgeship at stake isn't any federal judgeship but the Supreme Court itself."

The records of these 16 cases have become all the more important because of publicly released information about Roberts's policy views during an earlier time. As a young but high-ranking political appointee in the Reagan administration, Roberts was involved in, among other things, setting policy on issues of civil rights -- including those as fundamental as the right to vote and to be free from discrimination based on race, gender, national origin and disability. If Roberts continues to hold the views he appears to have expressed in the early 1980s, then his views on civil rights are out of the mainstream, and the people have the right to know that.

Specifically, and contrary to the intent of overwhelming majorities in both the House and the Senate, it appears that Roberts proposed a very narrow and crabbed interpretation of the Voting Rights Act that would essentially eviscerate the meaning of that law. Fortunately, his view did not prevail. But if a nominee to the Supreme Court believes in such a strained and narrow interpretation of such a fundamental right, then I believe he is not qualified to serve in that important position. The information we have requested from the administration would give us a more in-depth understanding of Roberts's views on this key civil rights issue, and we are entitled to it.

Many of us are also deeply concerned about some of Roberts's other positions from those early Reagan years. He repeatedly advanced narrow interpretations that would have undermined landmark and hard-won laws Congress passed to prohibit discrimination. As a young lawyer, Roberts advised the White House to delay fair-housing legislation. He urged the Justice Department not to intervene in a pending case and opposed a claim of gender discrimination, even though the assistant attorney general for civil rights, William Bradford Reynolds, believed the claim was based on "a very strong record" of gender discrimination. Are these still his views?

We already know that as deputy solicitor general Roberts advocated some of the same positions he took as a young lawyer in the Justice Department. For example, during his tenure in the Reagan Justice Department, Roberts tried to limit the scope of Title IX, which prohibits discrimination against women in educational institutions receiving federal funds.

Whether he still holds the views he expressed in the 1980s is a critical question. This is why it is so important for the Senate to receive the documents requested about the 16 cases he worked on in the solicitor general's office. For example, the Senate has requested information about Franklin v. Gwinnett, in which the Supreme Court unanimously rejected Roberts's argument to limit remedies available under Title IX to a teenage girl who had suffered flagrant sexual abuse.

No one has an automatic right to a lifetime position on the Supreme Court. A nominee to the high court must first demonstrate that he has a core commitment to constitutional rights and liberties. He must show that he is in the mainstream of modern judicial thought and that he would not use an ideologically motivated interpretation of our Constitution or laws to reverse the hard-fought gains we have made to make this nation more just. Judge Roberts's early record raises serious questions about his commitment to core constitutional values, and the Senate must have the requested information to fully and faithfully execute its constitutional obligation.

The writer is a Democratic senator from Massachusetts and a member of the Judiciary Committee.