As a young lawyer in the New Hampshire attorney general's office in 1970, David H. Souter experienced what he later described as "one of the most gratifying events of my life" -- appearing in federal court to defend New Hampshire's literacy test for voters.

The state lost. But the merits of its position -- that the Voting Rights Act was unconstitutional in abolishing its literacy test -- were not what excited Souter. For him, the case represented the opportunity for what he calls a "genuinely dialectical exchange" with an esteemed federal judge.

That reminiscence, on a Senate Judiciary Committee questionnaire listing his most important cases, was classic Souter, friends say. Throughout his career, the little-known New Hampshire judge has been less a legal zealot bent on a mission than a man with a detached, almost coldblooded attitude toward the law, one seemingly more interested in the intellectual contours of a legal argument than its real-world consequences.

Such an approach has served Souter well, allowing him to navigate the distance between the extremes in New Hampshire's Republican Party.

As appointed attorney general under conservative Gov. Meldrim Thomson Jr., Souter defended some of the governor's more controversial crusades, such as ordering state flags lowered to half-staff on Good Friday to commemorate the death of Jesus, or prosecuting Jehovah's Witnesses for obscuring the state motto, "Live Free or Die," on their license plates. One of his main backers in the Bush administration, vouching for his trustworthiness among conservatives, has been former New Hampshire governor John H. Sununu, who appointed Souter to the state Supreme Court.

Yet Souter's deepest friendships lie with more moderate, pragmatic Republicans, particularly two men who served with him in the attorney general's office, Sen. Warren B. Rudman and Concord lawyer Thomas D. Rath.

Rudman, a blustery former boxer, has been the moving force behind Souter's legal career; an inscribed picture from Souter, hanging in his Senate office, calls him "Primus Amicus Curiae," first friend of the court. Rath is a political activist who played the role of stage manager for his high school's production of "Our Town" and is still pulling strings, most recently by hosting strategy sessions at his lake house to prepare Souter for this week's confirmation hearings on his nomination to the Supreme Court.

While Souter also seems more temperamentally in tune with pragmatists like Rudman and Rath, it is not clear what that means for his potential service as a justice. On the one hand, Souter -- while conservative -- does not appear to be a Robert H. Bork, with pronounced and fixed views on a host of constitutional issues.

But conservatives believe, and liberals fear, that the difference could be much the same as that between Bork, whose nomination was rejected by the Senate, and the man who ultimately filled the position, Justice Anthony M. Kennedy. Three years after the bitter battle over Bork, Kennedy has turned out to be just as conservative, voting as Bork probably would have in nearly every instance.

Souter came to the state attorney general's office in 1968 after two years in private practice. Rudman, who became attorney general in 1971, quickly named Souter his deputy and came to rely on the young lawyer so much that -- as he described it at Souter's swearing-in as a member of the federal appeals court in Boston last May -- the only thing Rudman wrote that Souter failed to edit was a Mother's Day card.

In the attorney general's office, Rath joked, "My job was to take Warren to lunch and explain what David had just said."

Press reports at the time of Rudman's departure in 1976 say Gov. Thomson preferred a closer ally as his successor, but he ultimately selected Souter. As his deputy, Souter chose Rath, who became attorney general two years later, when Souter was named to the state superior court.

Former colleagues say Souter felt free to make policy in just one area, criminal justice. But there were a few points during his tenure when the real Souter appeared to emerge.

Souter broke with Thomson on the question of whether the state should allow casino gambling. In a 1977 op-ed piece in the Concord Monitor, he argued passionately that it would "change the character of the part of the world closest to us," luring tourists with the thrill of gambling rather than the beauty of the state's mountain scenery.

Souter was personally offended by what he viewed as the lawless conduct of more than 1,400 anti-nuclear protesters arrested for trespassing at the Seabrook power plant in May 1977.

When a local judge released one of the demonstrators with a suspended sentence and a small fine, Souter took the unusual step of racing to court to argue for a jail term, saying he found it "offensive that people should engage in mass criminal conduct" without being punished accordingly, making a "farce" of the criminal justice system.

As attorney general, Souter had a particularly feisty client in the governor. Souter and his staff also had a duty, former colleagues say, to defend Thomson's actions so long as they could "get up in court without turning purple," as Wilbur A. Glahn III, a lawyer formerly in the office, put it.

Souter's supporters emphasize the political distance between the two men. "I would be careful not to graft Meldrim Thomson onto David Souter," Rath said.

Souter was by all available accounts more energized by an arcane dispute with the Coast Guard over jurisdiction at Lake Winnipesaukee than by any of Thomson's more ideological causes. Yet as attorney general, Souter took three of Thomson's battles as far as the U.S. Supreme Court.

In one case, Thomson balked at filling out federal forms that required a racial breakdown of state employees, instructing personnel officials simply to list all state workers as "Americans." The Justice Department sued New Hampshire, and two federal courts upheld the regulations.

In a strongly worded petition to the Supreme Court, Souter argued that the regulation would lead to hiring quotas, and that it exceeded congressional power and violated the privacy rights of state employees. He even compared the questions to interrogations about workers' sexual practices. The Supreme Court declined to hear the case. Religion and 'Live Free or Die'

Another case involved two Jehovah's Witnesses, George and Maxine Maynard, who said the state motto, "Live Free or Die," violated their religious beliefs. The couple was prosecuted for obscuring the words on their license plates, and George Maynard served 15 days in jail.

But Souter argued that the Maynards' "acts, without explanation, are interpretable only as whimsy or bizarre behavior. Any communication peculiar to their acts falls far short of warranting First Amendment protection."

In an opinion by then-Chief Justice Warren E. Burger, the Supreme Court sided with the Maynards, saying: "The First Amendment protects the right of individuals to hold a point of view different from the majority and to refuse to foster, in the way New Hampshire commands, an idea they find morally objectionable."

In a case that reached the Supreme Court on an emergency basis during Souter's final days as attorney general, he defended Thomson's order to lower flags to half-staff on Good Friday, 1978, "to memorialize the death of Christ on the cross on the first Good Friday."

In handwritten papers filed on the morning of Good Friday, Souter argued that the declaration simply "recognizes Jesus as an historical figure without . . . endorsement of Christianity." But the justices, voting 5 to 4, blocked Thomson from lowering the flags.

When he swore Souter in as a superior court judge, Thomson gave Souter a small desk flag, flying at half-staff.

Souter had his heart set on a seat on the New Hampshire Supreme Court, and when Thomson first offered to name him to the superior court instead, Souter -- who saw himself more as an academic appellate jurist than a down-in-the-trenches trial judge -- turned him down. Thomson gave the offer to Rath instead.

After a sleepless night for both men, Souter told Rath that he had reconsidered because service on the trial court would probably make him a better appellate judge in the end. Rath agreed, and he succeeded Souter as attorney general.

During his five years riding circuit as a superior court judge, Souter adopted the unusual practice of calling in jurors after they reached their verdict, asking their impressions of the justice system, their reaction to the trial and whether they had understood his instructions.

In 1983, when Souter got his chance to join the New Hampshire Supreme Court, he quickly became known as its leading scholar, the most aggressive questioner of the five justices and a stickler for proper procedure.

As a trial judge, Souter once refused to preside over an uncontested divorce case in which a friend from his law firm of 10 years earlier, Ronald Snow, represented one of the parties. He will not sit on cases involving Rath's law firm.

"Even at Christmastime," said Kevin M. Leach, who clerked for Souter in 1987-88, "he wouldn't let us {law clerks} take him out to lunch," although he gave his clerk a bottle of sherry to start the new year.

Souter expects others to meet the same high standards he sets for himself.

"He's very tough at oral argument," said James Duggan, the state's chief public defender in appeals. "He asks very, very hard questions . . . and if you don't give him the answer he agrees with, he'll tell you why you're wrong."

"You know that when you're appearing in front of him he does not have a lot of tolerance for people who cite facts in the brief that aren't in the record, or describe a case inaccurately," said Manchester attorney Elizabeth Cazden.

Cazden recalled Souter once interrupting a colleague during oral argument. "He really quite sharply said to the lawyer something like, 'Before you continue, could you please tell us where you lifted the purported quote from the New Hampshire rules of evidence that appears on page 14 of your brief?' "

Souter apparently was concerned that the evidentiary rule had been quoted inaccurately, Cazden said, but it turned out he was reading from an outdated book. Shortly after that, she said, the lawyers received an apologetic note in which Souter -- through a court clerk -- acknowledged his error.

Some New Hampshire lawyers say the compassion that marks Souter's personal dealings is lacking from his approach to the law. "He leads with his intellect, not with his gut," Cazden said.

One case Cazden and others point to is Appeal of Albert and Edward Bosselait, two elderly brothers who sued for unemployment compensation benefits. The Bosselaits, 76 and 79 at the time of the case, had shared a single full-time janitor's position at a youth center and were laid off when the center decided to contract out custodial work.

The benefits were denied on the grounds that the unemployment compensation scheme required that employees be "ready, willing and able" to perform full-time work, something the brothers said they could not do because of their age.

At an administrative hearing before they had hired a lawyer, Edward Bosselait said he thought the law was "discriminating against old fellas." But Souter tossed out the brothers' bias claim, saying it had not been properly raised at the administrative hearing stage.

"Where he says you're supposed to cite the statute at the hearing -- that, to me, is not realistic for two laid-off janitors to cite 42 U.S.C. section 791," said the Bosselaits' lawyer, Bruce Friedman. "It was an informal hearing in front of lay people two weeks after they get the letter in the mail" denying benefits. Looking Back to the Magna Carta

Souter's dissent in a 1986 probate case seems to epitomize his narrow approach to constitutional interpretation. Souter invoked the doctrine of "original intent" in a way that has raised alarm among liberal groups who say that approach would invalidate decisions like Brown v. Board of Education.

The case, In re Estate of Henry Dionne, turned on whether it was legal to force citizens to pay $175 a day in fees to have the state's part-time probate judges hear disputes over wills and estates on days they were not regularly scheduled to sit.

The majority of the court ruled that the fees violated a provision of the New Hampshire constitution that all citizens are "entitled . . . to obtain right and justice freely, without being obliged to purchase it."

In a dissent that he listed on his Senate questionnaire as among his 10 most significant opinions, Souter agreed that the fees were a bad idea. The majority, he said, "is, if anything, moderate in its condemnation" of the fee arrangement. "If, therefore, that system were subject to the regulation of the judicial branch in accordance with its own notions of good public policy, I would join with the court in bringing the system to an end."

But, he said, the language of the New Hampshire constitution had long been interpreted "in the sense in which it was used at the time of its adoption." The court's task was therefore limited to determining the meaning of the language as it was understood in 1784, when the state constitution was ratified, he said.

Looking back as far as commentary on the clause of the Magna Carta of 1215 from which the New Hampshire provision was derived, Souter said history made clear that the provision did not cover fees such as those paid to the probate judges.

"Upon this point a page of history is worth a volume of logic," Souter concluded, quoting a famous line from his hero, Justice Oliver Wendell Holmes, who served on the Supreme Court from 1902 to 1932.

Souter's name first surfaced as a possible candidate for the Supreme Court three years ago, when Bork's nomination was sinking and Rudman promoted Souter as an alternative.

Since then, the possibility has been on Souter's mind. A New Hampshire lawyer recalls being at a party at which an off-color joke was told; when Souter was asked what he thought of it, the lawyer said, he replied, "Don't you think I learned something from Bork and Ginsburg?" Douglas H. Ginsburg, a judge on the U.S. Circuit Court of Appeals for the District of Columbia, withdrew himself from consideration for the Supreme Court after President Ronald Reagan nominated him in 1987 when it was reported that he had used marijuana several years earlier.

Still, when Bush named Souter to the federal appeals court in Boston early this year, Rudman and Rath insist they had to push their reluctant friend into accepting. Rath said in an interview that Souter had hoped to cut back on his lengthy hours at work and was concerned about taking on the responsibilities of a new job.

On the night that President Bush announced his selection of Souter for the Supreme Court, the judge and his old friend Rudman went down to the Senate Dining Room for a quiet dinner.

"He was in a state of shock . . . bewilderment, daze," Rudman recalled, wondering how the president had settled on him, of all the lawyers and judges in the country. Rudman gave Souter an old Army cot in his spare room, and raced off to appear on "Nightline" to plug the nomination.

"We talked about the fact that his life, assuming he was confirmed, would never be the same," Rudman said. "There was some sadness about that, on both of our parts."