The Supreme Court is set to hear Shaun McCutcheon v. Federal Election Commission, a case that could roll back campaign finance restrictions to those before the Watergate era. (Thomas LeGro/The Washington Post)

The conservative Supreme Court majority that has previously struck down a series of campaign finance restrictions for hampering political speech appeared ready Tuesday to toss another: the limit on the total amount an individual donor can spend on federal candidates.

Chief Justice John G. Roberts Jr. could be key to whether the final decision is a far-reaching one akin to the court’s divisive 2010 ruling in Citizens United, or a more surgical strike that leaves intact other parts of the Watergate-era law restricting campaign contributions.

The hour-long arguments exposed sharp and familiar differences on the court.

Liberal justices appointed by Democratic presidents said the restrictions help ensure that the voices of regular people are not drowned out by those of the wealthy. Conservative justices appointed by Republican presidents portrayed the laws as attempts by the government to silence First Amendment rights.

The stakes were clear at a news conference later in the day, when President Obama repeated his criticism of the Citizens United v. Federal Election Commission ruling that corporations and unions may spend directly on elections. He said the 2010 decision helped create the climate that led to the government shutdown.

During a news conference at the White House Tuesday, President Obama offered his views on "Shaun McCutcheon v. Federal Election Commission," a Supreme Court case that could roll back campaign finance restrictions to those before the Watergate era. (Associated Press)

“I’ve continued to believe that Citizens United contributed to some of the problems we’re having in Washington right now,” Obama said. He said some Republican lawmakers are willing to compromise but fear that deep-pocketed outside groups would target their reelection bids.

He said the court’s new case would go even further. “It would say anything goes — there are no rules in terms of how to finance campaigns,” Obama said.

If his description of the case was overstated — there would still be plenty of rules about how to finance campaigns — his sentiments also were part of the justices’ debate.

Restrictions on campaign contributions, Justice Ruth Bader Ginsburg said, “promote democratic participation” by forcing candidates to expand their fundraising efforts.

“Then the little people will count some, and you won’t have the super-affluent as the speakers that will control the elections,” she said.

Justice Antonin Scalia was sarcastic in responding, “I assume that a law that only prohibits the speech of 2 percent of the country is okay?”

The case at the court, brought by a wealthy Alabama political donor named Shaun McCutcheon and the Republican National Committee, challenges a contribution restriction that most Americans could not afford to exceed.

It imposes a $48,600 limit on contributions to candidates during a two-year election cycle, plus $74,600 total on giving to political parties and committees.

McCutcheon is not challenging the base limits on contributions to candidates — $2,600 for both primary and general elections — but said he wants to give the maximum to as many candidates as he wants. He can’t do that without violating the $48,600 limit.

At the heart of the current case is the framework created by the court’s seminal 1976 Buckley v. Valeo decision, which upheld limits on campaign contributions that Congress put in place two years earlier in response to the Watergate scandal. That ruling drew a distinction between contributions, which the court said could be limited to prevent corruption or the appearance of corruption, and expenditures, which the court determined were a form of direct personal expression.

That decision led to today’s campaign finance system, under which donors are restricted in how much they can contribute to candidates and parties but can donate endless sums to super PACs, which must spend their money independently of candidates and parties.

Roberts was sympathetic to McCutcheon’s argument about giving to multiple candidates. If one can give the legal limit to nine candidates without violating the government’s concern about corruption, Roberts wondered, why does the 10th tip the scale?

He said the government would not attempt a rule that says “The [Washington] Post or the New York Times can only endorse nine candidates.”

But Roberts also was concerned about Solicitor General Donald B. Verrilli Jr.’s argument that lifting the aggregate limits entirely would allow an individual to give more than $3.5 million to candidates through a related web of political parties and state committees.

“Is the possibility of prohibiting those transfers perhaps a way of protecting against that corruption appearance while at the same time allowing an individual to contribute to however many House candidates he wants to contribute to?” Roberts asked Verrilli.

Washington lawyer Erin E. Murphy, representing McCutcheon, said the restrictions cannot be reconciled with free-speech rights.

“These limits simply seek to prevent individuals from engaging in too much First Amendment activity,” she said.

But she and Bobby R. Burchfield, a lawyer for Senate Minority Leader Mitch McConnell (R-Ky.), who argued that all contribution limits should be removed, were sharply challenged by Justice Elena Kagan.

Kagan, who represented the government in the Citizens United case when she was Obama’s solicitor general, said removing the limit on contributions to parties and committees would allow congressional leaders to hit up each party’s big donors.

“So the speaker, the majority leader, can solicit $3.6 million to all the party members and you’re telling me there’s just no special influence that goes along with that?” she asked.

Justice Samuel A. Alito Jr., whose replacement of retired Justice Sandra Day O’Connor has shifted the balance of thinking on the court about campaign finance restrictions, said the multimillion-dollar figures were based on “wild hypotheticals” and would require an unlikely or illegal level of coordination. But, like Roberts, he said there might be a middle ground. “These aggregate limits might not all stand or fall together,” he said.

At one point of the discussion, Scalia seemed to be asking Verrilli to defend the current system in which individuals could give unlimited amounts to super PACs and other committees, but not to political parties.

Verrilli said that was a result of the court’s precedent that “independent expenditures do not present a risk of quid pro quo corruption that allows their regulation.”

Kagan piped in, “I suppose that if this court is having second thoughts about its rulings that independent expenditures are not corrupting, we could change that part of the law.”

The case is McCutcheon v. Federal Election Commission .

Matea Gold contributed to this report.