The 43-member Congressional Black Caucus formally opposed the nomination of John Roberts to be chief justice of the United States today, saying too many questions and concerns remain about his civil rights record.

Led by CBC chairman Rep. Mel Watt (D-N.C.) and Del. Eleanor Holmes Norton (D-D.C.), the caucus urged the Senate to reject Roberts’ confirmation when the matter comes to the floor. The Senate Judiciary Committee completed questioning Roberts last week and is expected to vote on the matter Thursday.

Just one CBC member, Sen. Barack Obama (D-Ill.), will cast a vote on the nomination.

“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,” the CBC said in a statement. “Judge Roberts failed to answer any of our concerns.

“Service as Chief Justice of the Supreme Court is far too critical to our constituents to leave those concerns unanswered.”

The CBC said it tried to get those answers through a meeting with Roberts, additional documentation and questions it submitted to the Judiciary Committee. The group said that while the committee asked many of its questions, it was not satisfied with Roberts’ responses. The caucus argued that Roberts did not explain himself adequately and sidestepped many of the questions.

In particular, the CBC said Roberts did not adequately explain his positions on affirmative action and the Voting Rights Act.

“We were extremely disappointed that Judge Roberts’ responses to these questions were evasive and elusive and only heightened our concerns,” the CBC statement said.

Despite the CBC opposition and that of some prominent Democratic Senators, Roberts is expected to win appointment to the high court. President Bush nominated Roberts on July 19.