President Reagan nominated as chief justice yesterday a man whose conservative views are well-formed, well-known and nearly identical to the president's beliefs on virtually every fundamental social and legal issue of the day.

In 14 years as an associate justice, William Hubbs Rehnquist has been utterly consistent, even predictable, in his votes and opinions.

He has opposed busing and the right to abortion; he has fought expanded constitutional protection for blacks, women, criminal defendants and the news media. He has voted to allow religious exercises in public schools, for state aid to parochial schools and for nativity scenes in city parks. At the same time, Rehnquist has worked to limit access to the federal courts for those who object to such practices, as well as for those challenging presidential authority or controversial actions of federal administrative agencies.

Rehnquist has done these things in the belief, voiced consistently, that the role of the Supreme Court should be extremely limited, that it should restrain itself from intervening in the business of state and federal government and that the Constitution should be interpreted narrowly, and rarely.

Of all the chief justices in recent history, Rehnquist, 61, appears to bring to the job the most clear-cut ideological agenda.

He also brings unique talents. He is universally regarded as one of the smartest justices on the court; when speed and semantic skill are required in an opinion, he has often been chosen to write it.

He is friendly and unusually accessible, and is fond of engaging in off-the-record debates with reporters. In contrast to his hard-line views, he brings a light touch to his work, inserting pithy rhymes and wisecracks in some of his opinions and in his comments from the bench.

It has been just this combination of attributes -- intellectual prowess, an ability to get along with his colleagues and a firm ideological agenda -- that has engendered such admiration from conservatives and such fear from liberals.

The late civil rights leader Roy Wilkins told the NAACP in a speech in 1971 that Rehnquist "may accept you as a buddy, but his philosophy will kill you."

The same combination could potentially make him a stronger leader of the court than Chief Justice Warren E. Burger has been. Burger's relationships with other justices have sometimes been awkward and his intellectual skills doubted. While Burger and Rehnquist subscribe to many of the same views, many legal experts think Rehnquist is potentially more capable of molding the alliances necessary to implement them.

Rehnquist's appointment to the court by President Richard M. Nixon in late 1971 was almost accidental. He was an assistant attorney general but apparently was so little known to the president that, according to Watergate tapes released later, Nixon referred to him as "Renchburg" and described him as one of a "group of clowns" in the Justice Department.

At that time, Rehnquist was helping the Justice Department choose Supreme Court nominees to replace retiring Justices John Harlan and Hugo Black. After Nixon's first two choices -- Clement Haynsworth and G. Harrold Carswell -- were rejected in a storm of controversy, Rehnquist and other top department officials met to consider new candidates.

As Rehnquist later described it, the others suddenly asked Rehnquist to leave the room, telling him that he had now become a possible candidate for the court and that if a particular senator turned down the job, the president would tap Rehnquist. Shortly thereafter, Nixon announced the appointments of Rehnquist and Lewis F. Powell Jr.

Rehnquist's conservative credentials were already well established. After graduating first in his class from the Stanford Law School (Justice Sandra Day O'Connor was a classmate), Rehnquist clerked in 1952 for Justice Robert Jackson, writing a memorandum for Jackson urging him to vote against desegregation of the public schools in the South.

After Rehnquist settled into a law practice in Arizona, he began writing articles about his experiences at the court -- then entering the activist Earl Warren Era. The court, he wrote, was being steered by the bias of law clerks who held views that were "to the left" of both the court and the country.

"Some of the tenets of the liberal point of view which commanded the sympathy of a majority of the clerks I knew," he wrote, "were extreme solicitude for the claims of communists and other criminal defendants, expansion of federal power at the expense of state power, great sympathy toward any government regulation of business, in short, the political philosophy now espoused by the court under Chief Justice Earl Warren."

In Arizona, Rehnquist became friendly with Richard Kleindienst, who brought Rehnquist with him to the Justice Department after Nixon was elected in 1968. As legal counsel to the department, Rehnquist was instrumental in forming the tactics the administration used to combat antiwar demonstrations. In a 1969 speech, he referred to demonstrators as "the new barbarians," declaring that they constituted a "threat to the notion of a government of law which is every bit as serious as the crime wave in our cities."

Rehnquist's record on civil rights, including his memorandum for Justice Jackson, his opposition to a Phoenix public-accommodations law and allegations that he had harassed black voters while a poll-watcher in Phoenix, was the main point of controversy during his confirmation hearings. He denied the harassment allegations.

Since Rehnquist joined the court, only one issue of a personal nature has arisen. In 1982, he entered George Washington University Hospital for what the court officially said was treatment of severe and chronic back pain. Further inquiry revealed that, in an effort to withdraw from a powerful prescription drug he had been taking to reduce pain, he had suffered a significant drug reaction that caused "disturbances in mental clarity."

Observers at the court had noticed Rehnquist slurring his speech and taking long pauses between sentences, but they were unable to determine the cause. After the hospitalization, his speech seemed normal, and no further health problems have come to public attention.

He did, however, generate a brief flurry of publicity in 1984 when he decided to preside as a trial judge in a federal court in Virginia in order to refresh his understanding of the trial process. He dodged reporters at the trial.

Some observers attributed Rehnquist's restlessness to boredom. He has demonstrated slight interest in the more mundane cases that crowd the high court's docket, and there has even been talk that he might retire from the court prematurely. Although he denies being bored, in recent years he has undertaken demanding speech-making obligations and is writing a book on the history of the court.

No boredom has been reflected in his opinions and dissents on major controversies before the court.

He has said he believes that goals and quotas and other forms of "reverse discrimination" are blatantly unconstitutional.

Dissenting in a case in which the court upheld a voluntary affirmative-action plan, Rehnquist said that "there is perhaps no device more destructive to the notion of equality than the . . . quota.

"Whether described as 'benign discrimination' or 'affirmative action,' the racial quota is nonetheless a creator of castes, a two-edged sword that must demean one in order to prefer another . . . . No discrimination based on race is benign . . . . No action disadvantaging a person because of his color is affirmative."

He also dissented bitterly in 1977 when the court overturned a New York law making it a crime to sell contraceptives to persons under 16.

If "those who valiantly but vainly defended the heights of Bunker Hill in 1775," he wrote, "could have lived to know that their efforts had enshrined in the Constitution the right of commercial vendors of contraceptives to peddle them to unmarried minors . . . it is not difficult to imagine their reaction."

In numerous opinions, he has objected to expanding constitutional rights of women as brought about in a series of court rulings, and he wrote the opinion upholding their exclusion from the draft.

Rehnquist generally believes that the court should not create rights not explicitly mentioned in the Constitution, no matter who the beneficiaries are.

Such exercises of power by the court, he said in objecting to the right of the press to attend trials, are "basically unhealthy." It is, he wrote, "basically unhealthy to have so much authority concentrated in a small group of lawyers who have been appointed to the Supreme Court and enjoy virtual life tenure . . . . "

Rehnquist has almost always voted in favor of narrowing the church-state gap, favoring, among other things, much greater aid to nonpublic schools than the court as a whole has allowed.

"The court," he has written, "apparently believes that the Establishment Clause of the First Amendment not only mandates religious neutrality on the part of government but also requires that this court . . . throw its weight on the side of those who believe that our society as a whole should be a purely secular one. Nothing . . . requires such an extreme approach."

Recent tallies have shown that, in criminal cases, he votes against defendants and for police more than any other justice. He objects to the controversial "exclusionary rule" under which illegally seized evidence may be thrown out of court, saying it hinders the search for truth.

He has written several opinions narrowing the reach of the Miranda rule, designed to protect suspects in police custody from interrogation outside a lawyer's presence.

He also consistently votes in favor of implementing the death penalty in the states.