WASHINGTON - On the opening day of confirmation hearings, Senate Republicans advised Supreme Court nominee John Roberts against responding to probing questions from Democrats on divisive issues: "Don't take the bait," said Texas Sen. John Cornyn.

Democrats promised to use the days of hearings to question Roberts on abortion, civil rights, privacy, election rights, capital punishment, judicial activism and the powers of the presidency and Congress.

President Bush chose Roberts to be the nation's chief justice, and at age 50, the appellate judge has the potential to shape the high court for decades.

Sen. Edward M. Kennedy, D-Mass., said the Senate must determine whether Roberts "has demonstrated a commitment to the constitutional principles that have been so vital in advancing fairness, decency and equal opportunity in our society."

Republicans warned Roberts against responding to "litmus-test questions."

"Don't take the bait," said Sen. John Cornyn, R-Texas, in his prepared statement. "Do exactly the same thing every nominee, Republican and Democrat alike, has done. Decline to answer any question you feel would compromise your ability to do your job. The vast majority of the Senate, I am convinced, will not punish you for doing so."

Roberts smiled and said merely, "Good morning," as he left for the hearings from his suburban Maryland home today. Outside the Supreme Court, across the street from the Capitol, several dozen demonstrators carried signs that said "Confirm Roberts" and "Stop Abortion Now." Court officers stood shoulder-to-shoulder to keep demonstrators at a distance.

Lawmakers were devoting the first day of the weeklong hearings to opening statements - from the 17 men and one woman on the Senate Judiciary Committee, from the three senators who were introducing Roberts and from the nominee himself.

Less than three years after first donning a judge's robe, Roberts seemed on a path toward speedy confirmation.

A turbulent week that included the funeral of William H. Rehnquist, his mentor and the man he hopes to replace, Roberts' renomination for chief justice and controversy over the government's tardy response to Hurricane Katrina didn't seem to cause any new problems for the nominee.

Liberal, civil rights, civil libertarian and abortion rights groups have come out against him, but not one of the Senate's 100 members has declared opposition.

"I expect these hearings will show that you have the appropriate philosophy to lead our nation into the future," said Sen. Mike DeWine, R-Ohio, and a Judiciary Committee member, in a written copy of his opening statement.

How Roberts answers questions from the panel's 18 members about his record as a conservative lawyer in the Reagan and George H.W. Bush administrations could affect the confirmation vote by the full Senate, expected before the end of September. The Supreme Court begins a new term Oct. 3.

Roberts originally was chosen to succeed retiring Justice Sandra Day O'Connor. But Rehnquist's death prompted the president to renominate him for chief justice.

Senate Democrats plan close questioning of Roberts now that he is slated to move all the way from a junior judge on the U.S. Circuit Court of Appeals for the District of Columbia to the top spot on the Supreme Court.

"This hearing is the only opportunity for the American people to examine what kind of justice John Roberts will dispense," said Sen. Patrick Leahy of Vermont, the top Democrat on the committee, in an advance copy of his opening statement.

Dianne Feinstein, D-Calif., the only woman on the committee, said in her prepared statement that she planned to ask Roberts about "the constitutional right to privacy" as it deals with abortion rights.

"I am concerned by a trend on the court to limit this right and curtail women's autonomy," Feinstein said. "It would be very difficult for me to vote to confirm someone to the Supreme Court whom I knew would overturn Roe v. Wade."

Roberts also will face questions on his ability to lead the current roster of eight strong-willed justices, all older and with more experience.

"The next chief justice will have the potential to change the court's image in the eyes of many as a superlegislature and to bring consensus to the court which has made a hallmark of 5-4 decisions, many of which are inexplicable," committee chairman Arlen Specter, R-Pa., said in his prepared opening statement.