The liberal push to expand the Supreme Court has turned into a surprise headache for Joe Biden late in the campaign, as activists on the left push him to endorse the addition of several justices but the swing voters he is courting show little interest in the idea.

On Thursday, Biden sought to make a nod to both camps by announcing that as president he would name a bipartisan commission to propose changes to the Supreme Court and federal judiciary, potentially placing a volatile issue on his agenda early in his prospective presidency.

The announcement gave Biden, who is wary of partisan court-expansion plans, a way to address the issue hours before his final debate with President Trump. But there were signs it would not fully resolve the matter, as Trump tweeted that Biden “wants to Pack the Court with Radical Left crazies” and a liberal group denounced the commission idea as insufficient.

The carefully negotiated rollout of Biden’s position, in a clip from a forthcoming episode of CBS’s “60 Minutes,” reflects the unexpected potency of an issue that Biden’s team initially believed could be dispatched by refusing to respond. Instead, the issue only gained steam as liberals sought payback for Republicans’ insistence in pushing through the confirmation of Judge Amy Coney Barrett with voting well underway in the presidential race.

In his comments Thursday, Biden agreed with activists that the current system is “getting out of whack” but reiterated that he does not favor the idea of simply adding justices and filling those slots with liberals.

“The last thing we need to do is turn the Supreme Court into just a political football [and] whoever has the most votes gets whatever they want,” Biden said in excerpts of the “60 Minutes” interview. “Presidents come and go. Supreme Court justices stay for generations.”

Biden has signaled that he instead wants broader changes that could incorporate the views of conservatives. Legal experts have proposed everything from term limits for justices to rotating them on and off the court to imposing a rough ideological balance to guaranteeing each president at least two nominations.

“It’s not about court-packing,” Biden said. “There’s a number of other things that our constitutional scholars have debated, and I’ve looked to see what recommendations that commission might make.”

Once a largely academic issue, the death of Ruth Bader Ginsburg and Senate Republicans’ response to it has focused attention on the potential for significant changes in the Supreme Court.

Senate Majority Leader Mitch McConnell (R-Ky.) is expected to hold Barrett’s final Senate confirmation vote roughly a week before Election Day. That contrasts with four years ago, when McConnell blocked President Barack Obama’s nomination eight months before the 2016 election on the grounds that it was too close to Election Day.

The commission proposal is the latest example of Biden’s political style, particularly his tendency to respond to pressure from the left without going as far as it wants. Some liberal groups want a Democratic Congress to add as many as four seats to the court and have Biden fill them all, creating an instant liberal majority.

Instead, Biden said the commission would have 180 days to come up with proposals, potentially giving his administration a window to determine whether a new era of bipartisanship is possible.

The liberal group Demand Justice called the proposal a “punt.”

“We certainly do not need a commission to tell us that Republicans are on the verge of stealing their second Supreme Court seat in four years and that the Roberts Court routinely sides with voter suppression schemes that advantage the Republican Party,” said Brian Fallon, the group’s executive director, referring to Chief Justice John G. Roberts Jr. “This proposed commission runs the risk of stalling momentum for serious reform.”

Others agreed that 180 days is a long time to wait for proposals.

“I worry about the timeline of the commission,” said Columbia University law professor David Pozen. “It’s not clear what remains to be studied. There are in the academic literature quite a menu of possible reforms.”

But there is no consensus even among Democrats on what changes make most sense.

Over the past four years, liberal activists have begun focusing on the federal judiciary in a new way, following decades in which conservatives paid far more attention to the makeup of the bench. Trump, with help from McConnell, has installed numerous young, highly conservative judges, including two Supreme Court justices and now potentially a third.

Many Democrats fear that even if they capture the White House and both chambers of Congress, the courts could throw out any liberal legislation, as well as impose limits on voting that would help Republicans.

“We went for a long time without even noticing what was going on at the court,” said Sen. Sheldon Whitehouse (D-R.I.), a Senate Judiciary Committee member and former U.S. attorney. “We’re now, I think, at the noticing stage.”

Some conservative thinkers have also been uneasy with the court’s growing politicization. Charles Fried, who was former president Ronald Reagan’s solicitor general, wrote an opinion piece this week in the New York Times that praised Biden for being open to shifting the court.

“I think it’s a good response,” Fried said Thursday. “The last thing we need is a bolus of young, smart, inexperienced ideologues on the far left to balance the reactionaries on the right.”

Adding justices purely to gain a partisan edge — called “court-packing” by critics — is not particularly popular, surveys show, a fact that may be reinforcing Biden’s reluctance. More than half of Americans opposed increasing the number of justices to give the winner of the presidential election more influence, according to a late September Washington Post-ABC News poll, while roughly a third supported the idea.

A New York Times-Siena College poll this month asked specifically whether Democrats should increase the size of the court if Trump’s Supreme Court pick is confirmed and Biden is elected president. Nearly 60 percent overall did not support adding justices, and 65 percent of independent voters opposed the move.

Still, the fast-evolving issue has left Biden struggling to come up with a way of talking about overhauling a branch of government that much of the country knows little about.

During his ABC News town hall last week, Biden for the first time suggested he would be open to some form of term limits for justices. The current lifetime tenure has elevated the stakes of each confirmation fight, making the battles increasingly bitter and pushing presidents to seek young, ideologically reliable nominees.

In one measure of the trend, Ginsburg was confirmed in 1993 by a 96-to-3 Senate vote after a generally amicable process. But two years ago, the newest justice, Brett M. Kavanaugh, was approved 50 to 48, with only one Democrat supporting him after a contentious confirmation process that included allegations of sexual misconduct and angry accusations of bad faith on both sides.

Some argue that removing the justices’ lifetime tenures would lower the temperature. The Constitution says little about the Supreme Court’s structure or jurisdiction, allowing Congress more room to shape its role than many recognize.

At the town hall, Biden cited an idea from former South Bend, Ind., mayor Pete Buttigieg to expand the bench from nine justices to 15. This “Balanced Bench” plan, which Buttigieg plucked from the Yale Law Journal, would provide for five Democrats, five Republicans and five justices selected from the lower courts by the 10 partisans.

Rep. Ro Khanna (D-Calif.) has a different plan, which includes 18-year term limits for Supreme Court justices. After their time on the high court, they would fill out their lifetime appointments on lower courts.

Khanna’s plan also would give each president the authority to appoint two new justices to the high court during each term, as a way of removing serendipity from the appointment process. If three vacancies occur during a single term, one would remain open until the next president takes office.

The United States is alone among advanced democracies in providing lifetime appointments for Supreme Court judges, Pozen said. The goal was to guarantee judicial independence, but the courts have arguably become more political, not less, and some justices now strategize over when it’s politically most advantageous to retire.

Other legal scholars have proposed prohibiting the Supreme Court from ruling on certain issues or requiring a supermajority to knock down acts of Congress.

Despite the impassioned arguments among activists, the dispute has caught the attention of few voters. During a Trump campaign call with reporters this month to argue that Biden would “pack” the high court, the president’s surrogates had to explain repeatedly what they meant.

The derisive term “court-packing” was initially used to describe Franklin D. Roosevelt’s failed 1937 push to add justices, after the court repeatedly blocked New Deal legislation. Democrats have sought to muddy the waters by accusing McConnell of “packing” the federal bench with his aggressive push to confirm conservative justices.

Democratic fears that the Supreme Court could knock down a Biden agenda have brought together liberal activists focused on a variety of issues, from climate to civil rights.

“There is broad recognition that Democrats have very little choice but to expand the court,” said Shaunna Thomas, co-founder of UltraViolet, a women’s rights organization. “I think people are very front-foot-forward on court-packing.”

But Biden explicitly rejected the idea during his primary campaign, warning of an indefinite partisan tit-for-tat.

“I’m not prepared to go on and try to pack the court, because we’ll live to rue that day,” he told the website Iowa Starting Line in July 2019.

But when it became clear Republicans would fill Ginsburg’s seat, Senate Minority Leader Charles E. Schumer (D-N.Y.) told Democratic senators that “everything is on the table” when it comes to changing the Supreme Court.

He repeated that in a private call with members of the House Progressive Caucus at the end of September, said Rep. Andy Levin (D-Mich.), who was on the call.

“I think you have to realize how violated we all feel,” Levin said. “I don’t think that really has to do with where you are on a political spectrum in the Democratic Party.”

Fallon, with Demand Justice, said more Democrats will likely support a court overhaul after Republicans vote to confirm Barrett, which is expected as soon as next week. And still more will offer various measures after the election, he predicted.

“This is now going to be a permanent part of the conversation, alongside other democracy fixes like getting rid of the filibuster and adding D.C. as a state,” Fallon said. “This is now right alongside those proposals that have become consensus positions in the Democratic Party the last couple years.”