Justice Stephen G. Breyer said this week that advocates of expanding the Supreme Court to dilute the power of its conservative majority should “think long and hard” about the risk of making justices appear more political and eroding public confidence in the court.

Breyer, one of the court’s three liberals, defended its independence by pointing to a decision to resist President Donald Trump’s attempts to draw the court into lawsuits seeking to overturn Trump’s election defeat.

In a speech at Harvard Law School on Tuesday, Breyer said that the court’s authority depends on “a trust that the court is guided by legal principle, not politics.”

He added, “Structural alteration motivated by the perception of political influence can only feed that latter perception, further eroding that trust.”

President Biden has said he is “not a fan of court-packing,” although he has pledged to create a bipartisan commission to study possible changes to the court. Nevertheless, some Democrats and liberal activists say that adding seats to the court is the only way to blunt the court’s conservative majority.

Some Democrats have called for expanding the number of justices to the Supreme Court in order to shift its ideological leaning. (Blair Guild/The Washington Post)

They contend that it is a proper and logical response to what they say was a form of court-packing by Senate Republicans. The GOP-led Senate refused to fill a vacancy that came open during Barack Obama’s presidency but then rushed to confirm Amy Coney Barrett just days before the 2020 presidential election.

Breyer has been cool to the idea in the past — as have other justices. He said his intent in the lecture — named the Scalia Lecture for Justice Antonin Scalia, who died in 2016 — was to “make those whose initial instincts may favor important structural change or other similar institutional change, such as forms of court-packing, think long and hard before they embody those changes in law.”

He acknowledged that judges are nominated by political parties because of their judicial philosophies and that politicians, the media and the public broadly think of them as conservative or liberal.

But, he said, proposed structural changes in the judiciary could deepen distrust.

“If the public sees judges as politicians in robes, its confidence in the courts — and in the rule of law itself — can only diminish, diminishing the court’s power, including its power to act as a check on other branches,” he said.

The court is widely acknowledged to have a 6-to-3 conservative majority, but Breyer even took issue with that. He pointed to the justices’ decision to defy Trump’s insistence that it get involved in the results of the November election.

“The court’s decision in the 2000 presidential election case, Bush v. Gore, is often referred to as an example of its favoritism of conservative causes,” Breyer said. “But the court did not hear or decide cases that affected the political disagreements arising out of the later 2020 election.”

Trump has said the court, which includes three of his nominees, displayed a lack of “guts” and let down conservatives.

Breyer, in addition, noted liberal victories in the court.

“It did uphold the constitutionality of Obamacare, the health-care program favored by liberals,” he said. “It did reaffirm precedents that favored a woman’s right to an abortion. It did find unlawful certain immigration, census and other orders, rules or regulations favored by a conservative president.”

Breyer said that “at the same time it made other decisions that can reasonably be understood as favoring conservative policies and disfavoring liberal policies. These considerations convince me that it is wrong to think of the court as another political institution.”

Breyer also used his speech to call for more compromise and fewer dissents from the bench, even as he acknowledged that such agreement is not always possible when it comes to matters of “principle or conscience.” As an example, he pointed to cases on state rules prohibiting churches from holding indoor services amid efforts to prevent the spread of a deadly disease such as covid-19.

“Compromise certainly should have seemed possible in this case,” Breyer said of state limits on indoor religious services during the coronavirus pandemic. “Why didn’t all members agree?”

The answer, he said, is “just too much a matter of conscience,” with some justices believing the state must be especially careful when imposing restrictions on religious worship and others thinking that freedom must give way to scientific opinion about public health risks.

In February, the justices were sharply divided over the issue in a California case, with five of nine writing to explain their reasoning. The court’s conservative majority said the state must allow churches to resume indoor worship services.

Breyer joined the dissent, in which Justice Elena Kagan wrote that “Justices of this Court are not scientists.”

Breyer, 82, is the court’s oldest justice and has his own political considerations to make. He was nominated to the court in 1994 by President Bill Clinton, a Democrat, and is under considerable pressure to retire now while another Democrat, Biden, is in the White House and Democrats hold narrow control of the Senate.

Many Democrats and liberal activists are urging him to make an announcement soon; Biden has said that when there is an opening, he will nominate the court’s first African American woman.

Justice Ruth Bader Ginsburg resisted similar calls to retire when Obama was president, and her death in September at age 87 gave Trump the chance to nominate Barrett, who just turned 49.

Breyer gave no hint in his speech about whether he is considering stepping down.