The Senate convenes the first confirmation hearing for a chief justice nominee in nearly two decades today, starting a week of admonitions and questions for John G. Roberts Jr. certain to probe deeply into the conservative views of a man who could shape the court's direction for decades to come.

The Judiciary Committee's 10 Republicans and eight Democrats will focus on Roberts, 50, an appellate court judge and President Bush's choice to succeed the late William H. Rehnquist, starting at noon with opening statements in the historic Caucus Room of the Russell Senate Office Building.

Analysts from both parties say the Judiciary Committee's toughest questions -- and Roberts's likeliest risk of a slip -- will center on a few issues that have dominated liberal-conservative judicial debates for years. Many will touch on the balance of power between Congress, the executive branch and the courts. Others will resonate more viscerally with ordinary people: abortion rights, voting rights and questions of balancing environmental protections against jobs and property development.

And in the tragic aftermath of Hurricane Katrina, concerns about the treatment of poor people and minorities could heavily influence the thrust of some of the questioning.

"Americans will have the opportunity for the first time to hear Judge Roberts's views on the major issues," Sen. Edward M. Kennedy (D-Mass.), the committee's most senior member, said in an interview. Katrina's devastation underscores the hearing's importance, he said.

"What the American people have seen is this incredible disparity in which those people who had cars and money got out, and those people who were impoverished died," Kennedy said. The question for Roberts, he said, is whether he stands for "a fairer, more just nation" or will he use "narrow, stingy interpretations of the law to frustrate progress."

Roberts, largely unknown outside legal circles two months ago, was Bush's choice to replace retiring Supreme Court Justice Sandra Day O'Connor. Before his confirmation hearings could start, however, Chief Justice Rehnquist died of cancer on Sept. 3. Bush quickly nominated Roberts to succeed his former boss and mentor, and urged the full Senate to vote on his confirmation by the month's end.

Roberts has been practicing for the hearings for weeks in front of panels of colleagues posing as committee members. But in many ways, friends say, he has been preparing for this week his entire life: dazzling his classmates at Harvard Law School, enthusiastically toiling as a government lawyer under Presidents Ronald Reagan and George H.W. Bush, and serving since 2003 as a judge on the U.S. Court of Appeals for the D.C. Circuit. Many Senate Democrats privately predict he will win confirmation comfortably, barring an unforeseen bombshell.

But the ride won't be free. In his years as a young lawyer in the Justice Department, White House and solicitor general's office, Roberts advocated conservative judicial philosophies in hundreds of memos and letters. Many, but not all, of those memos have been released, providing insights into his thinking and beliefs.

The following is a summary of Roberts's views on some of the key issues likely to arise during hearings:

Civil Rights

In his memos from the 1980s, Roberts showed himself to be a strong proponent of the Reagan administration's view that earlier measures to redress historic discrimination were themselves discriminatory because they granted preferential treatment based on race and sex.

Roberts repeatedly argued against affirmative action programs. He fought to limit the scope of civil rights laws, opposing, for instance, an eventually successful congressional effort to make it easier to prove voting rights violations. He wrote of the "perceived problem of gender discrimination" and criticized state efforts to address it.

In two memos, Roberts suggested that gender discrimination did not have to meet a heightened level of court scrutiny, a view at odds with the Supreme Court. Defenders note that Roberts did, in the first instance, point out that the position was the policy of then-Attorney General William French Smith.

In a 1981 memo, Roberts argued that while a school board "with a blanket policy of rejecting all blacks" may be discriminating, rejected applicants were not entitled to job offers and back pay unless they could prove that they "were more qualified than white applicants who were hired."

The law, then and now, requires only that applicants prove they were as qualified, said Chuck Cooper, the official to whom Roberts addressed his memo.

Privacy and Abortion

Senators will press Roberts on abortion and the right to privacy, which the Supreme Court has cited as the legal underpinning for legalized abortion. In his Reagan-era writings, Roberts referred to the "so-called right to privacy," expressing the view that such an "amorphous right" does not exist in the Constitution. He called abortion a "tragedy."

Twenty-four years ago, when Roberts was preparing O'Connor for her Senate hearing, he advised her not to state her position on the landmark 1973 Roe v. Wade case. "The proposition that the only way senators can ascertain a nominee's views is through questions about specific cases should be rejected," he wrote.

During Roberts's 2003 confirmation hearing for his current post as an appellate judge, he said only that he considered Roe a matter of settled law. Now that he is nominated to head a court that eventually could vote to overturn the case, senators will ask him how much weight a justice should give to court precedent and whether he thinks Roe was rightly decided.

Interstate Commerce

Democrats will seek Roberts's views on Congress's authority to pass a wide range of laws in the name of regulating interstate commerce. The "commerce clause" is especially important to liberal groups because it has enabled the federal government to override state resistance in areas such as voting rights.

Roberts's best-known comment on the topic came in his dissenting opinion as an appellate judge in a 2003 case known as Rancho Viejo. A California developer challenged a federal environmental law that impeded his planned project in a bid to protect a rare species of toad that lives only in California. Roberts said the commerce clause should not apply because the toads did not cross state lines. The liberal group Alliance for Justice called his opinion a "crabbed view of congressional power" that threatened "to undermine a wide swath of federal protections, including many environmental, civil rights, workplace and criminal laws."

Courts' Powers

In the 1980s, Roberts repeatedly argued that Congress had the power to strip the Supreme Court of the authority to hear cases on abortion, school prayer and other issues. Although Roberts would later write that such a move would be "bad policy," his supporters say he can expect tough questions this week.

Theodore B. Olson, a colleague who differed with Roberts at the time, later became solicitor general and this summer helped Roberts prepare for the hearing. In an interview, Olson said Roberts needs to explain the context of his arguments as a young Reagan administration lawyer. Part of Roberts's role at the time, he said, was to challenge the status quo and provoke debate. "That probably means that there are a disproportionate number of his memos where he was out there on the conservative side," Olson said. Roberts also has argued that the federal government -- and federal courts -- should be selective and cautious in challenging state laws. In a 1982 memo he lamented that the Justice Department did not help Texas defend a law -- eventually struck down -- that allowed public schools to turn away children of illegal immigrants.

Research editor Lucy Shackelford contributed to this report.

Nominee John G. Roberts Jr., left, speaks with Judiciary Committee Chairman Arlen Specter. Originally named to succeed retiring Justice Sandra Day O'Connor, Roberts will undergo confirmation hearings to be chief justice.Sen. Orrin G. Hatch, left, serves on the panel with Specter. Before the committee, Roberts will tap his background as an appellate court judge, as a lawyer in the private sector and as a political appointee.