Faith has factored into previous Supreme Court confirmations, but the John Roberts hearings may be the first to take place on consecrated grounds.

Evangelical minister Rob Schenck secretly blessed every piece of furniture in the three Senate hearing rooms where the Judiciary Committee will consider the Roberts nomination. The Washington activist, who heads the National Clergy Council, described the exercise as "an act of prayer, in preparation for this whole process."

The Supreme Court is central to all of the big Christian conservative issues, including the role of religion in public life and the legality of abortion and same-sex marriage. Schenck and other conservative leaders are hoping that President Bush has found a kindred spirit for them in Roberts, a lifelong practicing Roman Catholic.

The degree to which Roberts's religious beliefs may inform his judicial philosophy could be a significant line of questioning, especially given that Roberts is replacing Sandra Day O'Connor, a key vote on many contentious social issues. Conservatives distrusted O'Connor for the same reason that liberals are sorry to see her go: She supported abortion rights and took moderate stances on other social causes, including voting to strike down Texas's sodomy law, a 2003 case that was a turning point for gay rights.

The signals with Roberts are mixed. Liberal women's groups believe that based on his legal record, he may attempt to overturn Roe v. Wade. Conservative groups also have found material not to like in the Roberts dossier, such as the Supreme Court case he helped to prepare challenging a Colorado constitutional amendment excluding gays from anti-discrimination laws.

The issue for both sides is not so much what Roberts believes is right or wrong. Rather, it is the degree to which he believes religious morality may be permitted to influence public policy. Liberals believe in a firewall between church and state, but as Christian conservatives see it, the Supreme Court should allow elected officials to restrict abortions or permit a Ten Commandments monument to be displayed on public property, if those actions have voter support. Gary Marx, executive director of the conservative Judicial Confirmation Network, described the ideal judge as "a neutral umpire . . . who respects what state legislatures are doing and doesn't try to be a lawmaker from on high."

The Roberts nomination is the first since conservative Christians became a key Republican voting bloc and transformed their beliefs into a political movement. Members of Congress now take legislative action in God's name -- for instance, when they tried to save the life of Terri Schiavo, who was brain-damaged.

"They know there's a political current out there, and they know they have to deal with it," said Laura R. Olson, a Clemson University political science professor who studies religion and politics.

Judiciary members who have expressed curiosity about Roberts's religious views include Sen. Richard J. Durbin (D-Ill.), a liberal and a Catholic, and Sen. Tom Coburn (R-Okla.), one of the panel's most conservative members. Coburn queried Roberts privately about how his faith influences his work and ran into resistance. "He said, 'I'm very uncomfortable talking about that,' " Coburn told reporters, adding he intended to raise the issue again.

Others do not want to touch it, including Sen. Patrick J. Leahy (Vt.), the committee's ranking Democrat, who also is a Catholic. "Just as we're supposed to be colorblind, we should be religious-blind," he said. Sen. John Cornyn, (R-Tex.), responded angrily to a report that Durbin had asked Roberts about potential religious conflicts of interest, "We have no religious test for public office . . . and I think anyone would find that sort of inquiry, if it were actually made, offensive."

Bush helped to trigger the debate in summer 2002, after the 9th Circuit Court of Appeals banned the Pledge of Allegiance in schools because of the "under God" clause. "We need common-sense judges who understand that our rights were derived from God, and those are the kind of judges I intend to put on the bench," Bush declared then.

Barry W. Lynn, executive director of Americans United for Separation of Church and State, which opposes the Roberts nomination, said of Bush's remark, "In a sense we have to presume that he somehow vets people for their religion."

Democrats who push too hard could deepen a growing impression that they are secular elitists. According to a new survey by the Pew Forum on Religion and Public Life, 29 percent believe the Democratic Party is friendly toward religion, and 44 percent believe secular liberals have too much sway in the party.

Democrats were burned in 2003 when they blocked the nomination of Alabama Attorney General William H. Pryor Jr. to the 11th Circuit Court of Appeals, in part because of Pryor's personal opposition to abortion. Conservative groups ran ads suggesting Leahy and other Democrats were barring Pryor because of his Catholicism -- even though it was a Republican, Judiciary Committee Chairman Orrin G. Hatch (Utah) -- who asked Pryor about his Catholic faith during his June 11, 2003, confirmation hearing.

Some observers worry that Democrats will be drawn into a similar trap with Roberts, whose judicial record is sparse after two years on the U.S. Court of Appeals for the D.C. Circuit. Roberts weighed in on a variety of subjects as a lawyer for the Reagan administration, but those writings do not necessarily reflect his personal views.

"They want to get a read on the guy, and it's hard to find anything to grab onto -- so maybe [his Catholicism] would be an attractive line of questioning," said W. Clyde Wilcox, a Georgetown University government professor.

"You can understand a person better if you know the reason they've taken a position is from their faith," Wilcox said. But, he added: "Knowing someone is a Catholic doesn't really tell you where they are on abortion at all."

Patrick Trueman, senior legal counsel for the conservative Family Research Council, said that after surveying lawyers and reviewing Roberts's legal writings, and personal encounters with the nominee, "We have a measure of confidence that he would be better on our issues than Sandra Day O'Connor."

But Trueman also had high hopes for Anthony M. Kennedy, nominated by President Ronald Reagan in 1987 to replace Justice Lewis F. Powell Jr. Trueman, a Reagan Justice Department official, said the expectation within the Reagan administration was that Kennedy "would be opposed to Roe v. Wade based on his judicial philosophy."

Kennedy's religion attracted notice when it was reported that he had told then-Sen. Jesse Helms privately that he understood the North Carolina Republican's opposition to abortion "because I am a practicing Catholic." Questioned about the statement during his confirmation hearing, Kennedy said he was not trying to signal how he would rule in abortion cases. "It would be highly improper for a judge to allow his or her own personal or religious views to enter into a decision respecting a constitutional matter," he testified.

In 1992, Kennedy co-wrote the court's opinion in Planned Parenthood of Southeastern Pennsylvania v. Casey, which upheld a woman's right to an abortion but permitted certain state regulations.

One way senators could broach the issue would be through a section of the American Bar Association's Model Code of Judicial Conduct that states judges should not preside over cases in which they have a financial "or other" interest. Democrats are debating whether to ask Roberts to interpret the section in the context of a decision by some Catholic bishops last year to refuse Holy Communion to Catholic politicians who support abortion rights. If such a ban were extended to Supreme Court justices, would Roberts consider that a sufficient "other" interest?

Schenck, who is planning a round-the-clock prayer vigil during the hearings, says he does not have high hopes. "We just think that the majority of lawmakers are incapable of dealing with the faith issue in an informed and intelligent way," he said. "We can never know what the nominee will do. Only God knows that."