John Roberts (search) was sworn in late Monday afternoon before the Senate Judiciary Committee, where he vowed "to uphold the rule of law" and explained why he should be confirmed as the next chief justice of the U.S. Supreme Court.

After listening to more than three hours of opening speeches by members of the panel, Roberts said he was "humbled" by the confidence President Bush showed for him and vowed, "I will do everything I can to be worthy of the high trust he has placed in me."

He also conjured up several baseball analogies to drive home the point that he will live up to expectations that he interpret the law, not make it.

"Judges and justices are servants of the law, not the other way around. Justices are like umpires" in that they call the game as they see it, Roberts said in unwritten remarks that took only six-and-a-half of the 15 minutes allotted to him. "I will remember it is my job to call balls and strikes, not to pitch or bat.

"I have no agenda but I do have a commitment," he added. "If I am confirmed, I will confront every case with an open mind. I will fully and fairly analyze the legal arguments that are presented. I will be open to the views of my colleagues on the bench and I will decide every case based on the record according to the rule of law without fear or favor to the best of my ability."

After his remarks, the panel recessed for the day. Lawmakers on both sides of the aisle ran to the cameras to give their analysis.

"If it was a fight, nobody laid a glove on him. He did a great job," Sen. Lindsey Graham, R-S.C., told FOX News. "The only way he could be vetoed is through a filibuster, and after his opening statement today I don't think anyone could ever get the political capital to mount a filibuster against this guy."

During the first hearing day, at least one Democratic senator said that based on Roberts' record, he would vote not to confirm the nominee to be chief justice.

"Judge, if I looked only at what you've said and written in the past, I'd feel compelled to vote 'no,'" Sen. Joseph Biden, D-Del., said during the first day of the Senate Judiciary Committee's confirmation hearings for Roberts. "You dismissed the Constitution's protection of privacy as a 'so-called right,' you derided agencies like the Securities and Exchange Commission (search) that combat corporate misconduct as 'constitutional anomalies,' and you dismissed 'gender discrimination' as merely a, and I quote, 'perceived problem.'"

Biden did not say that he would oppose the nominee, but wanted to hear some further explanation from Roberts about prior statements and writings.

"This is your chance to explain what you meant by what you have said and what you have written," he said.

Roberts sat with little expression on his face as lawmakers made their opening remarks. In front of him was a blank notebook, giving clues to observers that his opening statement was going to be recited from memory.

Sen. Charles Schumer, a New York Democrat, has been urging Roberts to answer every question fully and completely on issues such as privacy and how much the government should intervene in national issues. In ascertaining Roberts' personal views on topics, Schumer made what seemed to be a reference to the Titanic and the ship's demise.

"We have seen maybe 10 percent of you — just the visible tip of the iceberg, not the 90 percent that is still submerged. And we all know that it is the ice beneath the surface that can sink the ship," Schumer said.

While he doesn't expect Roberts to share the same views as him, Schumer added that he will base his vote on two criteria: whether he answers his questions "fully so we can ascertain your judicial philosophy;" and whether that philosophy is in "the broad mainstream."

At least two committee Democrats used the impact of Hurricane Katrina (search) to note lingering inequalities in this country, one of many issues Roberts, if confirmed, is likely to confront on the nation's highest court.

"Our commitment to this founding principle is especially relevant today. Americans are united as rarely before in compassion and generosity for our fellow citizens whose lives have been devastated by Hurricane Katrina (search)," said Sen. Ted Kennedy, D-Mass. "The powerful winds and floodwater of Katrina tore away the mask that has hidden from public view the many Americans who are left out and left behind."

Added Sen. Patrick Leahy, D-Vt.: "If anyone needed a reminder of the racial divide that remains in our nation, no one can now doubt that we still have miles to go. I believe that the American people still want, expect and demand their government to help ensure justice and equal opportunity for all and especially for those who, through no fault of their own, were born into poverty."

But Republicans were quick to blast this approach.

"I believe the American people will see this for what it is," Sen. John Cornyn, R-Texas, said in a statement released while the hearings proceeded. "We ought not to appropriate a national tragedy in a misguided effort to further a political interest of any sort."

Committee Chairman Arlen Specter warned Roberts that the confirmation process may be a tough one because of all the political bickering going on in Washington.

"This hearing comes at a time of turbulent partisanship in the United States Senate, turbulent partisanship," the Pennsylvania Republican said, nothing that a "virtual meltdown" almost occurred in the chamber earlier this year as Democrats filibustered several of President Bush's other judicial nominees.

Most on Capitol Hill expect Roberts, 50, will ultimately win confirmation to be the nation's 17th chief justice of the U.S. Supreme Court, but the nominee will first have to face questions on everything from abortion, election rights, capital punishment, separation of church and state, civil rights and the death penalty.

Roberts also will face questions during the four to five days of hearings 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," Specter said.

Prior to the death of his mentor, Chief Justice William Rehnquist (search), Roberts was nominated to replace outgoing Justice Sandra Day O'Connor (search). After the chief justice's death, Bush renominated Roberts for the top court position and O'Connor agreed to stay on the court until her replacement could be confirmed. The last time a confirmation hearing was held for a chief justice was 1986.

GOP: Follow the 'Ginsburg Rule'

Roberts is not required to answer any questions, nor is he supposed to reveal his views on certain hot-button topics or how he would rule in a certain case.

Some Democrats on the Judiciary Committee were displeased in 2003 when Roberts evaded their questions during hearings on his appeals court nomination.

"You ask about their temperament, demeanor — you don't get into the issues," Alan Simpson, a former Republican senator from Wyoming who sat on the Judiciary Committee, told FOX News.

He suggested Roberts follow what's known as the "Ginsburg rule," named after Justice Ruth Ginsburg who, during her own confirmation hearings, refused to answer many questions on those grounds and was told by Democratic senators that refusing to answer was fine by them.

"If it [confirmation process] hangs up on abortion and gay rights and the social issues, boy, I think the people of America will have their thumb down their throat," Simpson added. "You can play games, you can ask things … that no one else would ever answer, and his best response is, 'I'll just respond as Justice Ginsburg did.'"

Sen. Orrin Hatch, R-Utah, said despite Democrats' arguments, the Ginsburg rule "is not a myth, it is a reality."

"I was on this committee in 1993. Justice Ginsburg was not telling mythological tales when she refused to answer questions over 60 times," he continued, noting that Ginsburg herself said, "no hints, no forecasts, no previews."

But Democrats argue that they have to ask tough questions of such an important nominee.

"What are we going to ask him — what he had for breakfast? We've got a responsibility here to ask this guy some hard questions," Democratic strategist Bob Beckel told FOX News.

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

"Don't take the bait," said Sen. John Cornyn, R-Ariz. "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."

As the hearing got underway, Robert introduced an extended roster of family members appearing in the committee room, including his young daughter Josephine and son Jack, who gained national notoriety for fidgeting during President Bush's nomination announcement of Roberts in July.

Specter earned a laugh when he responded to Roberts' introductions.

"Judge Roberts had expressed his appreciation to have the introductions early. He said the maximum time of the children's staying power was five minutes. And that is certainly understandable," Specter said.

Hearings began with opening statements from all 18 members of the committee; each statement lasted as long as 10 minutes. Roberts will then be introduced in three five-minute speeches. After three hours and 15 minutes of speechifying, Roberts will finally deliver his opening statement.

Senators who won't be in the hearing room will be the so-called "Gang of 14" (search). These are moderate senators who have all agreed that the president should get his nominee unless there are extraordinary circumstances surrounding the nomination. So far, nothing has arisen that seems to concern the gang.

Several liberal, civil rights, civil libertarian and abortion rights groups have come out against Roberts, 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 (search), R-Ohio.

Weighing The Questions

How Roberts answers questions about his record as a conservative lawyer in the Reagan and George H.W. Bush administrations will play heavily into the confirmation vote by the full Senate, expected before the end of September. The Supreme Court begins a new term Oct. 3.

Dianne Feinstein, D-Calif., the only woman on the committee, said 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."

Specter has said he will not ask Roberts if he would vote to overturn Roe v. Wade (search), the landmark decision that legalized abortion. But Specter did say he planned to ask Roberts whether there is a right to privacy in the Constitution.

Sen. Charles Grassley, R-Iowa, said answering such questions would be giving in to liberal interest groups who "only want judges who will do their political bidding on the bench, regardless of what is required by the law and the Constitution."

Roberts also will face questions on his ability to lead the court's justices, all older and with more experience.

Since his initial July nomination, Roberts has visited lawmakers on Capitol Hill several times. In addition, the White House released more than 70,000 documents related to his legal and professional work in the Reagan administration but has refused to release solicitor general documents.

But Democrats have been decrying the amount of paperwork released on Roberts, saying they need more information to ensure the next potential Supreme Court justice will not be too extreme and who will serve the best interests of the country.

Republicans say Roberts is a solid conservative and point to his credentials, arguing that he's the best person for the job.

"They ought to be respectful ... and bear in mind the importance of the court's role in America," former associate White House counsel Helgi Walker told FOX News. "I think everybody in Washington agrees, Democrats and Republicans alike, that John Roberts will be confirmed to be our next chief justice ... I hope senators don't try to use these hearings for their own personal agendas."

But Jack Quinn, former White House counsel to President Clinton, said that while the questions posed to Roberts would be probing, they would also be fair.

"It's the United States Senate. I'm sure some will try to use it as a platform," Quinn said. But, "I do think there are a good many questions of that kind that need to be explored thoroughly with this man," he added.

Roberts can be confirmed by a majority vote of the 100-member Senate, and most of its 55 Republicans praise his qualifications, intellect and demeanor.

Roberts was expected to join the Supreme Court in October as an associate justice before his name was elevated to the chief's post, which would allow him to follow in the footsteps of one of his mentors. Roberts clerked for Rehnquist in 1980. As an appellate lawyer, he argued 39 cases in front of Rehnquist and the other justice.

"I'm very much aware that if I am confirmed, I would succeed a man I deeply respect and admire, a man who has been very kind to me for 25 years," said Roberts, who helped carry Rehnquist's casket into the Supreme Court building for the public viewing last week.

FOX News' Brian Wilson and The Associated Press contributed to this report.