Justice Stephen Breyer has served on the Supreme Court for 27 years. Today he may be known best for his refusal to leave.

Liberals outside the court have been publicly pressuring the 83-year-old Democratic appointee to retire and give President Biden a chance to name a younger successor. Breyer has said he has yet to decide. He has tried to avoid politics as he weighs the choice. A professed optimist, he appears to have faith that Democrats are not headed for another GOP-engineered Senate stall of a nominee, as President Barack Obama experienced in 2016.

A similar rosy view and idealism permeate his latest book, even as Breyer addresses the declining legitimacy of the Supreme Court in the public eye. He seeks to provide a historical backdrop to current public discussions about reforming the court. Like Breyer’s opinions and general life outlook, “The Authority of the Court and the Peril of Politics” reflects a balancing of interests and reverence for history. He declines to face up to the deepening gulf between blocs of justices, seen most recently in orders involving asylum policy, coronavirus measures and abortion rights.

But Breyer does temper his optimism with some pragmatism.

He warns that these politically polarized times threaten public confidence in the high court. He understands that the court’s currency depends on Americans’ trust in an impartial decision-making process, even when they abhor the final rulings. Yet Breyer discounts the court’s own contribution to “the peril of politics.” He looks outward to politicians and the news media and criticizes the partisan context in which they describe the Supreme Court.

In the Senate, he laments the pattern of party-line votes for judicial nominees, and he criticizes the tendency to identify jurists by the presidents who appointed them and their respective political affiliations: “Senators will often describe a nominee they oppose as too liberal or too conservative, and thus ‘outside the mainstream.’ What senators say, reported by the press to their constituents, reinforces the view that politics, not legal merits, drives Supreme Court decisions.”

Breyer rejects the notion that the court itself, with its 6-to-3 conservative majority, is politicized. “Political groups may favor a particular appointment,” he writes, “but once appointed a judge naturally decides a case in the way that he or she believes the law demands. It is a judge’s sworn duty to be impartial, and all of us take that oath seriously.”

He avoids any discussion of the ways the justices themselves reinforce the media narrative. Last session, some of the most important cases split along 6-to-3 political and ideological lines, such as when the majority curtailed voting rights and union organizing. In August, over liberal dissent (including from Breyer), the conservative majority ruled against Biden administration initiatives related to asylum policy and the pandemic eviction moratorium. In the most startling move, the majority this month allowed a Texas abortion law that patently conflicts with Roe v. Wade to take effect.

The partisan tensions have been evident. But Breyer in his book insists that divisions between conservative and liberal justices arise from jurisprudential differences, not political or ideological ones. As evidence that the court is not as conservative as often described, he notes that the justices declined to hear Donald Trump’s challenges to the 2020 election and that the court has in the past reaffirmed precedent favoring a woman’s right to end a pregnancy.

Yet Trump’s election arguments were stunningly meritless, as lower-court judges repeatedly observed. And the justices have left in place the Texas ban on abortion after six weeks of pregnancy, at least for the near future. They also have agreed to hear a Mississippi case in the upcoming session that could eviscerate nationwide precedent that prevents states from banning abortions before a fetus is viable, that is, can live outside the woman. Asked about the Texas case in a Washington Post Live interview Monday, Breyer said, “I did think it was very wrong, and I wrote a dissent.” The jurist who’s embarked on a busy promotional tour added that, in light of his assertion that the court is not so divided, “the timing wasn’t very good for my book.”

Breyer fails to confront what could be on the horizon for reproductive rights, just as on the retirement question, he declines to address partisan worries about what could happen to a Biden Supreme Court choice if Democrats’ one-vote Senate majority slips.

Confirmation politics have only grown nastier since 2016, when Republican Senate Majority Leader Mitch McConnell blocked all action on Obama’s nomination of Merrick Garland to fill the seat of the late justice Antonin Scalia. That vacancy remained until Trump took the White House in 2017; Trump eventually named three justices: Neil Gorsuch, Brett Kavanaugh and Amy Coney Barrett.

Still, Breyer’s larger point about the importance of confidence in the court stands up: No one inside or beyond its walls should take the public trust for granted. The justices’ opinions guide the behavior of all Americans, and the court must have the authority to act as a constitutional check on the other branches of government. While presidents have at times condemned the court’s decisions, they have adhered to them.

That adherence among presidents and trust among the public were built over time. Breyer summons history to argue against structural changes to the current bench. Some liberal advocates have pushed for an increase in the number of seats to counterbalance the conservative dominance. “I aim to make those whose reflexive instincts may favor significant structural (or other important) changes, such as forms of court packing, think long and hard before embodying those changes in law,” Breyer writes.

Soon after Biden came into office, he appointed a bipartisan commission to explore such proposals, as well as term limits for justices, now appointed to lifetime tenure, and measures that would enhance transparency and ethical guidelines. The commission’s report, which will stop short of any formal recommendations, is expected this fall.

One term-limit option would set justices’ tenure at 18 years. Breyer, a 1994 appointee of President Bill Clinton, is headed for at least 28 years at this point. Justice Ruth Bader Ginsburg served for 27 before her death last September. Trump was able to push through Senate confirmation of Barrett, Ginsburg’s successor, just days before the November presidential election.

“The “The Authority of the Court and the Peril of Politics” is a tiny book (barely 100 pages) that tracks a speech Breyer presented in April at Harvard. Breyer first witnessed the inner workings of the Supreme Court a half-century ago as a law clerk. He went on to teach law at Harvard, serve as Senate Judiciary Committee chief counsel and sit on a Boston-based federal appellate court.

Breyer highlights historic rulings that were controversial but widely accepted: Marbury v. Madison (1803), establishing the court’s authority to determine the constitutionality of acts of Congress; Brown v. Board of Education (1954), ending the doctrine of “separate but equal”; Bush v. Gore, settling a presidential election.

Breyer writes that Brown and other school desegregation decisions helped promote respect for the court. But he also acknowledges that the court moved slowly — and strategically — on race in the late 1950s and early ’60s. “For quite a few years after rendering its decision, the Court carefully chose which cases to take, sometimes avoiding ones that might thwart its ambitions in Brown — for example, those that asked the Court to set aside laws forbidding interracial marriages.”

The Supreme Court did strike down such laws in the 1967 case Loving v. Virginia. Breyer describes the 13-year gap between Brown and Loving as “a calculated part of the Court’s enforcement strategy.” He said that demonstrated the court’s attention to public opinion. But then he writes, with characteristic balancing: “One could well claim that here the Court had entered the realm of politics. Or was it merely protecting its invaluable institutionalized authority? It is hard to say.”

At every turn, Breyer avoids ascribing political motives to the justices. “If I catch myself headed toward deciding a case on the basis of some general ideological commitment, I know I have gone down the wrong path, and I correct course. My colleagues think the same way. All studiously try to avoid deciding a case on the basis of ideology rather than law.”

It’s hard to imagine some of Breyer’s colleagues saying that of one another. In recent opinions, justices have, in fact, questioned each other’s motives.

The tone of Breyer’s book reflects his bridge-building nature. On the Supreme Court, he is known for trying to craft consensus. He helped negotiate a compromise when the court first upheld Obama’s Affordable Care Act. In that 2012 case, Chief Justice John Roberts joined the four liberals, over right-wing dissents. Breyer uses that case, involving what he describes as “the health care program favored by liberals,” as another piece of evidence that the court cannot be labeled “conservative.”

That 2012 decision was indeed notable, especially for Roberts’s vote to preserve what has become known as Obamacare. But in the scheme of politically charged cases, it is an exception, not the rule.

Breyer, to be sure, is readier than most of his colleagues to give ground for a compromise ruling. He presumes that dueling sides can come together and that all will be good in the world. To some critics, including liberals pressing him to retire immediately, Breyer can appear naive. If Democrats were to lose their one-vote Senate majority, Republicans would wield greater influence over Biden’s choice of a successor and perhaps outright block the nominee.

When I interviewed Breyer this summer, he told me he had not yet decided when he would step down. He focused on his new role as the senior liberal, since last year’s death of Ginsburg, and attempts to persuade his colleagues on the right wing to consensus decisions.

“It is, of course, much easier to burrow with the like-minded than to engage meaningfully those who disagree, but such engagement is what democracy looks like,” Breyer writes at one point in his book, urging greater civic education and participation in public life.

Yes, engage, he advises. But for his colleagues, he also suggests some avoidance. “One way of ensuring . . . public acceptance,” he writes, “is for the Court to apply legal rules or practices that minimize the number of cases likely to provoke strong political disagreements.”

That is clearly the tactical approach of a justice in the left-wing minority. But the court has already scheduled for the 2021-22 session cases on abortion and Second Amendment rights, among other contentious subjects.

Facing such tough cases, Breyer offers another upbeat maxim for building public confidence: “The more diverse the jurisprudential views on a court,” he writes, “the more important compromise among the judges becomes.” Whether that ideal becomes reality depends not on Breyer but on the right-wing justices who now, by the sheer power of their numbers, control the Supreme Court.

The Authority of the Court and the Peril of Politics

By Stephen Breyer

101 pp. $19.95