Sen. Patrick Leahy, the ranking Democrat on the Senate Judiciary Committee, said today that he would cast his vote in favor of confirmation of John G. Roberts as Chief Justice of the United States despite numerous reservations. He said he took Roberts at his word that he does not have "an ideological agenda."

The announcement, on the eve of tomorrow's committee vote on the nomination, is especially significant in light of yesterday's announced opposition by the Senate's Democratic leader, Sen. Harry M. Reid (Nev.).

Massachusetts Democrats Senators Edward M. Kennedy and John Kerry and New Jersey Democrat Jon S. Corzine also announced this morning that they would vote against Roberts.

Democratic Senators Max Baucus (Mont.) and Tim Johnson (S.D.) said today they would support Roberts's confirmation.

No observer believes Roberts's nomination will be rejected. Rather, the vote is being viewed now as a precursor to the next nomination, expected in a few weeks, of a replacement for retiring Justice Sandra Day O'Connor. Leahy said he hoped his vote would encourage the president to avoid appointing an extreme conservative to the court.

Leahy, who questioned Roberts closely and aggressively during last week's confirmation hearings, said in a statement that that his vote "presents a close question."

With it, he said, "I do not intend to lend my support to an effort by this President to move the Supreme Court and the law radically to the right. . . . Balance and moderation on the Court are crucial."

Leahy criticized Republicans on the committee for encouraging Roberts to be unresponsive to questions about his judicial philosophy. And he criticized Roberts for taking the Republicans' advice in many of his answers.

Leahy also expressed concern that Roberts had not demonstrated "appropriate deference" to acts of Congress, but rather demanded an "unrealistic exactitude in drafting laws that no collective body could meet."

On the other hand, Leahy said, "I am encouraged that he will respect congressional authority" to protect the environment, "ensure equal justice and provide health care and other basic benefits" to Americans.

Also, Leahy said, Roberts "left me with the understanding that he would not seek to overrule or undercut the right of a woman to choose. I trust that he is a person of honor and integrity and that he will act accordingly."

Suggesting that his vote would not be popular with his constituency, Leahy said that "Roberts is a man of integrity. I can only take him at his word that he does not have an ideological agenda."

Kennedy, who was relentlessly critical of Roberts during the hearings, said that while Roberts is a "highly intelligent nominee," his evasions "made a mockery of the confirmation process. At the end of the four days of hearings, we still know very little more than we knew when we started. . . .

"No one is entitled to become Chief Justice of the United States," Kennedy said. "The confirmation of nominees to our courts -- by and with the advice and consent of the Senate -- should not require a leap of faith. Nominees must earn their confirmation by providing us with full knowledge of the values and convictions they will bring to decisions that may profoundly affect our progress as a nation toward the ideal of equality," he said.

"Judge Roberts has not done so. His repeated allegiance to the rule of law reveals little about the values he would bring to the job of Chief Justice of the United States," Kennedy said. "The record we have shows a clear hostility to our progress toward our common American vision of equal opportunity for all of our citizens."

Kerry, the Democratic presidential candidate in 2004, said "I refuse to vote for a Supreme Court nominee who came before the Senate intent on demonstrating his ability to deftly deflect legitimate questions about his views, opinions and philosophy.

"If he is confirmed -- and he may well be -- the Roberts Court will shape the course of constitutional law for decades to come," Kerry said. ". . . . With that much at stake, Judge Roberts needed to show us where his heart is. Instead he recited case law and said little about what he really thought."

The statements came shortly after Leahy and three other senators met with Bush at the White House to talk about the vacancy created by the decision by O'Connor to retire.

Bush originally nominated Roberts for the O'Connor vacancy but after the death of Chief Justice William H. Rehnquist, he renominated him to be chief justice.