WASHINGTON – If President Bush is looking for a potential Supreme Court nominee with conservative credentials who would inspire a minimum of fuss at a confirmation hearing, he may turn to Judge John Roberts Jr., say fans of the Buffalo native, who sits on the U.S Court of Appeals for the District of Columbia.

“Almost alone among the serious candidates, Judge Roberts combines youth, intellect, temperament, judicial philosophy, and confirmability,” said a former associate White House counsel, Bradford Berenson, who worked on judicial selection under President Bush.” He is young, he’s bright, he’s conservative, he’s well respected across the ideological spectrum, and he’s unlikely to run into effective opposition if he were nominated.”

But liberal critics say not so fast – a pre-eminent Supreme Court litigator before ascending to the bench, Judge Roberts argued for overturning the landmark abortion rights decision Roe v. Wade while he was deputy solicitor general in the Reagan administration.

A potential battle over his nomination could come down to the question of whether a lawyer should be held responsible for the arguments he makes on behalf of a client.

At 50, Judge Roberts has the youth and experience to make him an attractive pick, should Chief Justice Rehnquist, who is ill with thyroid cancer, retire.

The judge earned solid conservative credentials serving in the administrations of President Reagan and the first President Bush. Prior to becoming a judge, he was a lawyer in private practice who argued 24 cases before the Supreme Court.

“I think he’s got an excellent shot,” said Washington lawyer Tom Goldstein, who frequently litigates before the Supreme Court. “He was the most respected member of the Supreme Court bar,” prior to taking to the bench, he said.

And his nomination would present the potential for a personal homage to the chief justice: Judge Roberts served as his law clerk a quarter-century ago after earning his bachelor’s and law degrees at Harvard.

President Bush appointed him a year and a half ago to the prestigious D.C. Circuit court, which has served as a stepping-stone for Supreme Court judges. His appointment was confirmed without objection in the Senate.

While his judicial experience has been brief, a short judicial tenure is not unprecedented for a nominee to the top court. And it could help him prevail in a confirmation hearing because he has not had the time to rack up an extensive paper trail that would help senators pin down his personal views.

On the other hand, some conservatives worry that the lack of a clear record does not allow them a clear picture of how he would rule from the bench.

“He is certainly an upstanding guy, but David Souter was an upstanding guy,” said a conservative legal observer who asked not to be named, referring to the justice appointed by President George H.W. Bush who has frustrated conservatives with decisions that frequently side with liberals on the bench.

But others are convinced Judge Roberts is on their side.

“John Roberts is a serious conservative, a mainstream conservative – a constitutionalist,” said the executive director of the Committee for Justice, a group that advocates for President Bush’s judicial nominees, Sean Rushton.

Judge Roberts’s Senate confirmation hearing to the appellate bench was relatively smooth. Republicans squeezed in three nominees on one day – Judge Roberts, as well as Judges Jeffrey Sutton and Deborah Cook, who were considered more controversial and received the lion’s share of the questions.

The scrutiny of Judge Roberts centered on his role in co-authoring a Supreme Court brief for the Reagan administration arguing that Roe v. Wade was “wrongly decided and should be overturned.” The case was called Russ v. Sullivan, and the government argued that it could prohibit doctors in federally funded family planning programs from discussing abortions with their patients.

The brief stated the Supreme Court’s conclusion in Roe, “that there is a fundamental right to abortion … finds no support in the text, structure, or history of the Constitution.”

The Alliance for Justice, a liberal group that tracks judicial nominees, declared that Judge Roberts had “a record of hostility to the rights of women and minorities. He has also taken controversial positions in favor of weakening the separation of church and state and limiting the role of federal courts in protecting the environment.”

The group pointed out that Judge Roberts also argued on the government’s behalf that court supervision should be lifted in school desegregation cases; that public high schools should be able to perform religious ceremonies at graduations (a position rejected by the Supreme Court), and that religious groups had a right to meet on school grounds (a position the court accepted.)

His defenders argue that no individual brief should be held against him because a lawyer is duty-bound to represent his clients and make all reasonable legal arguments in the client’s favor. “There is extraordinary cover there,” said Mr. Goldstein. “It was his job to sign the brief.”

Senator Hatch, a Republican of Utah who chaired the confirmation hearing, said it was “patently unfair” to attribute the arguments personally to Judge Roberts. “Attorneys are required to represent their clients,” he said. “This fact is so fundamental that it should go beyond reproach.”

Mr. Hatch noted that the nominee’s clients also included welfare recipients that he represented for free, a prison inmate who alleged cruel and unusual punishment, Hawaii’s Democratic attorney general and governor arguing in favor of a race-conscious program to benefit native Hawaiians, and a Nevada regulatory agency seeking to limit property development around Lake Tahoe.

“He is very confirmable,” said a former counsel to Senate Majority Leader Frist, Manuel Miranda. “He has had a rich variety of clients that cannot be easily characterized as liberal or conservative.”

The legal director of People for the American Way, a group that is preparing to fight conservative nominees, Elliot Mincberg, said the judge’s past briefs and some court rulings “have been troubling.”

Because of his short record as a judge, “his testimony would be very important. “The abortion brief in particular “would create very serious problems from the beginning.”

Mr. Mincberg does not accept the argument that Judge Roberts had no choice but to sign the brief.

“John was the political deputy of the solicitor general’s office. He was not a lowly trial attorney who has to follow orders. As the political deputy, he helps make that policy,” Mr. Mincberg said.

At his hearing, Judge Roberts said the government briefs were written through a “very broad collaborative process,” sometimes involving 10 government agencies.

He raised the example of John Adams representing a British soldier involved in the Boston massacre. “There is a long standing tradition in our country … that the positions a lawyer presents on behalf of a client should not be ascribed to that lawyer as his personal beliefs or his personal positions,” he said.

The Senate Judiciary Committee confirmed his nomination 16-3.

Supporters expect Judge Roberts will receive friendly treatment from the Washington press corps as well.

“He is already well-known to the Washington media and goes to all the parties and the meetings,” said Mr. Miranda.

Perhaps most importantly, Judge Roberts is also well known to the justices, having argued before them on many occasions. The administration would be nominating “someone 20 or 30 years younger than the justices as the chief justice,” said Mr. Miranda. “They need someone the justices know.”