Justice William H. Rehnquist is noted now for his conservative dissents from Supreme Court opinions. But he could be on the crest of a wave in a Ronald Reagan presidency, for in most respects he appears to be just the sort of Supreme Court justice the Republican platform had in mind.

Rehnquist voted against legalizing abortion. He opposes extensive "forced busing." He cherishes private property. He thinks the government is helping destroy the family. And he, more than any other current justice, wants to get the federal government off the states' backs.

Should Reagan be elected, should four or five of the current justices retire in the next four years (as is expected) and assuming a Reagan administration was true to its campaign rhetoric, a look at Rehnquist's views provides some insight into how the court might change.

If Rehnquist's dissents became majority sentiment, legal gains in the field of women's rights would be sharply curtailed. Affirmative action programs involving racial quotas would be illegal. Public aid to nonpublic schools would become more readily available. States would be freer to pass laws requiring the death penalty, and carry them out.

And the court itself, which Reagan has accused of "unsurpation of power that threatens our system of self-government" would become less powerful. It is not desirable, Rehnquist said in a recent dissent, "that such authority be excercised by such a tiny numerical fragment of the 220 million people who compose the population of this country."

Beyond the specific issues, the mindset and the rhetoric of the court could change dramatically over time. Some illustrations:

In 1977, the court overturned a New York law making it a crime to sell contraceptives to minors under 16 and to advertise contraceptives.

Rehnquist, dissenting, had this to say: If "those who valiantly but vainly defended the heights of Bunker Hill in 1775 . . . 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 through such means as window displays and vending machines located in the men's room of truck stops . . . it is not difficult to imagine their reaction . . . ."

"The majority of New York's citizens are in effect told [by the court] that however deeply they may be concerned about the problem of promiscuous sex and intercourse among unmarried teen-agers, they may not adopt this means of dealing with it."

In 1974, the court overturned the Massachusetts conviction of a man charged with wearing a small U.S. flag sewn to the seat of his pants. The majority held that the law regulating "contemptuous" display of the flag was too vague to pass constitutional muster.

Dissenter Rehnquist said this: "The significance of the flag, and the deep emotional feelings it arouses in a large part of ou citizenry, cannot be fully expressed in the two dimensions of a lawyer's brief or of a judicial opinion.

"But if the government may create a private proprietary interest in written work and in musical and theatrical performances by virtue of the copyright laws, I see no reason why it may not . . . create a similar governmental interest in the flag by prohibiting even those who have purchased [It] from impairing its physical integrity.

"For what they have purchased is not merely cloth dyed red, white and blue, but also the one visible manifestation of two hundred years of nationhood . . . ."

In the court's last term, the majority upheld a $105 million award to the Sioux nation to compensate it for the taking of the Black Hills by the government and white settlers in the 1800s.

"That there was tragedy, deception, barbarity and virtually every other vice known to man in the 300-year history of the expansion" of the country "cannot be denied." Rehnquist said. "But in a court opinion, as a historical and not a legal matter, both settler and Indian are entitled to the benefit of the biblical adjuration: 'Judge not, that ye be not judged.'"

In his 1979 dissent from the court's opinion in the Weber case, upholding a private affirmative action program, Rehnquist was at the height of outrage.

The court's opinion, he said bitterly, "is ahead of its time. It could more appropriately have been handed down five years from now, in 1984 . . . .

"There is perhaps no device more destructive to the notion of equality than the numerous clauses -- 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."

In the 1978 term, he found a "nagging sense of unfairness" about the treatment of a corporate defendant denied a jury trial in a securities fraud civil action. In 1976 he held that states could deny equal treatment to illegitimate children so long as the denial is "not mindless and patently irrational."

Rehniquist's views generally have an underlying consistency, a theme. The federal courts have usurped too much power, he says again and again. The states, their courts and their legislators have been reduced to impotence.

His dissents are filled with words like "intrusion" "invasion" and deference." And his speeches mirror his pronouncements from the courts.

He is tired, he has said, of the Civil War equal protection amendment to the Constitution being used to protect not only blacks (for which it was designed) but women, illegitimate children and others. According to Rehnquist, it has been used as a "cat-of-nine-tails to be kept in the judicial closet as a threat to legislatures which may, in the view of the judiciary, get out of hand and pass 'arbitrary, 'illogical' or 'unreasonable' laws."

He is weary, Rehnquist told a University of Missouri audience in March, of the idea that the Constitution consists solely of the Bill of Rights.

It does "contain important guarantees of individual rights against action by federal and state governments," he said. "But the Constitution as a whole is a charter which created a national government and empowered it to limit not only the authority of states but the liberties of individuals . . . ."

Rehnquist is not highly regarded among legal scholars at universities. A recent National Law Journal survey, in which law professors were asked to grade each justice, gave Rehnquist an overall grade of "c," lower than all except Chief Justice Warren Burger. Liberal justice William Brennan received the highest overall grade, B plus.

The Republican platform, however, presumably more meaningful in a Reagan presidency, would have undoubtedly given him an "a," had it engaged in the same exercise.

For example, the platform said this about busing: It "has been a prescription for disaster, blighting whole communities across the land with its divisive impact. It has failed to improve the quality of education . . . ."

Rehnquist, in a joint dissent with Justices Lewis Powell and Potter Stewart in January, took a similar position, saying: "It is increasingly evident that use of the busing remedy to achieve racial balance can conflict with the goals of equal educational opportunity and quality schools" and can cause "white flight," thereby leading to urban disintegration.

The Republican platform called for appointment of judges who have a strong belief "in the decentralization of the federal government and efforts to return decision-making power to state and local elected officials."

Rehnquist, in a dissent last court term from the decision requiring open trials in most situations, said this: "To gradually rein in, as this court has done over the past generation, all of the ultimate decision-making power over how justice shall be administratered, not merely in the federal system but in each of the 50 states, is a task that no court consisting of nine persons, however, gifted, is equal to."