US President George Bush has nominated another conservative judge to replace the late William Rehnquist as chief justice of the Supreme Court. While some Democrats have expressed reservations about John Roberts it is expected the Senate will confirm his appointment. Bush urged the chamber to act quickly so the 50 year-old could be installed in time for the start of the new Supreme Court term on October 3.Rehnquist died of cancer on Saturday at the age of 80. He served under several administrations starting with Richard Nixon’s in 1971. Rehnquist carved out a record as one of the most conservative jurists in U.S. history on the Supreme Court. The panel was deeply divided on such contentious issues as abortion, the death penalty and separation of church and state.