The Senate is to debate and vote this week on Roberts' elevation to chief justice to replace William Rehnquist who died Sept. 3. Last week, the Senate Judiciary Committee voted 13-5 -- with three Democrats voting with the 10 Republicans on the committee -- to recommend the nomination.
With 55 Republicans in the Senate the appointment was not in doubt, but at least 12 Democrats have said they would also vote to approve Roberts' nomination.
President Bush nominated Roberts to replace Justice Sandra Day O'Connor, who said she wanted to retire. But when Rehnquist died, Bush changed Roberts' nomination to be chief justice and asked O'Connor to stay on. Bush kept his goal of having Roberts approved by Oct. 3, the opening of the new Supreme Court session.
Bush said he would act quickly to find a replacement for O'Connor and Democrats have promised a tougher fight against that nominee than against Roberts, who many Democrats opposed because of his vague answers on questions on voting and women's rights.