"I intend to cast my vote against the nomination when the Senate meets here next week," Reid said on the Senate floor.
"For me, Mr. President, this is a very close question. But I must resolve my doubts in favor of the American people, whose rights would be in jeopardy if John Roberts turns out to be the wrong person for this job," he said.
Reid said the main factor that soured him on Roberts was the series of memos Roberts wrote on civil rights while a member of the Reagan administration. Reid concluded the worst from them.
"It is now clear that as a young lawyer, John Roberts played a significant role in shaping and advancing the Republican agenda to roll back civil rights protections," he said.
But Roberts did publicly win the support Tuesday of Georgia Republican Sen. Saxby Chambliss, with whom he met on Tuesday. Chambliss explained to senators that the Reagan administration was against quotas, not affirmative action, and that President Reagan had always argued a big difference existed between the two. After their meeting, Chambliss said Roberts deserves to be confirmed.
"If integrity counts, if honesty counts, if knowledge of the law counts, if family values counts, If being a true American counts, you can't vote against this man," he said.
Sen. Patrick Leahy of Vermont, the ranking Democrat on the Senate Judiciary Committee, told FOX News that Reid's announcement is not any intention to speak on behalf of the Democratic Party, but is rather a report of his own plans. Leahy said Reid has not applied pressure on rank and file Democrats who are starting to stake out positions on the man named to succeed the late William H. Rehnquist (search).
Reid may be laying down a strong marker, however, Leahy said. Caught in the hallway, Sen. Edward Kennedy, D-Mass., who also serves on the Judiciary Committee, told FOX News that he too would oppose Roberts and expected other Democrats to make their positions known soon.
Later, however, Reid said he thinks Roberts' confirmation is not in doubt. He's going to get "plenty of votes," he said.
Other Democrats also gave indications that Roberts' confirmation is almost assured. Montana Sen. Max Baucus of Montana said Tuesday he is leaning toward voting for Roberts.
"I'm inclined to vote for him unless something else comes up," Baucus said after a meeting of his party's senators. "It's a close call."
Added Sen. Ben Nelson, D-Neb.: "I've not seen anything that would cause me to vote against" Roberts.
As party leader, Reid had urged fellow Democrats not to announce their positions until the conclusion of last week's confirmation hearings for Roberts. Roberts has strong Republican support and appears headed for easy confirmation. Judiciary Committee Chairman Arlen Specter, R-Pa., on Monday announced his intention to support the nominee.
During his floor remarks, Reid said Roberts' nomination does not rise to the level of "extraordinary circumstances," the code phrase used to suggest whether Democrats would employ a filibuster (search), the procedural tool used to block a nomination from getting a full Senate vote. At least 60 votes are needed to overcome a filibuster and force a vote.
Again later, Reid said he had not felt the need to go to the well and push Democrats to oppose Roberts.
Senate Democrats met privately Tuesday to discuss the nomination, which has drawn strong opposition from critics who argue that Roberts might vote to overturn Roe v. Wade, the 1973 ruling that established the constitutional right to an abortion. Civil rights organizations also oppose Roberts' confirmation, citing some of the positions he took while with the Reagan administration and his refusal to disavow them at confirmation hearings.
The Senate Judiciary Committee is scheduled to vote on the nomination on Thursday. The panel includes 10 Republicans and eight Democrats — two of whom are members of the party's leadership. The outcome of that vote is expected to serve as a preview of the level of bipartisan support Roberts can command in the Senate.
The Senate is made up of 55 Republicans, 44 Democrats and one independent. If the Senate Judiciary Committee approves Roberts' nomination and sends it to the full Senate, a simple majority is needed to confirm him.
The AFL-CIO, the nation's largest labor federation, and the Service Employees International Union, which has 1.8 million union members, both announced their opposition to Roberts Tuesday as critics mounted a last-minute effort to discourage Democrats from voting for him.
"The record available to us at this time does not allow us to say with any degree of confidence that Judge Roberts has an understanding of, or commitment to, protecting the hard-fought rights and protections of working families, including their right to equal opportunity," said AFL-CIO President John Sweeney.
The Congressional Black Caucus, which is made up of the House's African American lawmakers and Sen. Barack Obama, D-Ill., also announced its opposition.
"Judge Roberts' civil rights record and views remained the most controversial and unexplained part of his record when the Judiciary Committee hearing concluded, just as his civil rights record and views had been the most controversial part of his record when the hearing began," said Rep. Mel Watt, D-N.C., the CBC's leader.
FOX News' Brian Wilson and The Associated Press contributed to this report.