The Supreme Court’s conservative majority expressed doubts that South Carolina’s congressional map is an unconstitutional racial gerrymander at oral arguments Wednesday in a case that could bring Democrats one step closer to winning the House.

The challenge is centered on a newly redrawn congressional district represented by Republican Rep. Nancy Mace, who beat a Democrat in 2020 but whose new district under the proposal cements a GOP tilt. She is regularly thrust in the spotlight for bucking her party but joined a small contingent of conservative Republicans in voting to oust former Speaker Kevin McCarthy (R-Calif.) from the top leadership post.

Republican state lawmakers’ map shifted some 30,000 Black Charleston-area residents out of the state’s 1st Congressional District, which Mace currently represents. 

South Carolina is one of multiple southern states’ whose congressional maps face racial gerrymandering or vote dilution legal challenges, a sprawling set of cases that could impact control of the House, particularly with such a narrow political split.

The South Carolina Republican lawmakers insist the boundaries were changed for partisan reasons, but a three-judge panel struck down the map, ruling that race was the predominant motivating factor by finding the mapmaker used a racial target.

During the roughly two-hour argument Wednesday, the Supreme Court’s conservatives pierced an attorney representing a Black voter and a racial justice group about how they could disentangle race from politics, given that the two are closely correlated.

“I’m not saying you can’t get there, but it does seem that this would be breaking new ground in our voting rights jurisprudence,” said Chief Justice John Roberts.

Conservative Justice Brett Kavanaugh emphasized how the map, in addition to Black-majority precincts, also moves out of the 1st District tens of thousands of residents in West Ashley, an area of Charleston. 

“It’s predominantly white, isn’t it?” Kavanaugh noted.

Republicans represented the 1st District, which runs along South Carolina’s coast, for more than 35 years until Democrat Joe Cunningham in 2018 narrowly won in a major upset.

In the next election, Cunningham lost to Mace in another close race. But two years later, after the 1st District was redrawn, Mace went on to win reelection in 2022 by a more comfortable 14 percentage points.

A resident of the district and the South Carolina State Conference of the NAACP are suing over the design, alleging it is a racial gerrymander in violation of the 14th Amendment’s Equal Protection Clause.

They point to how lawmakers moved nearly 200,000 residents in or out of the 1st District while keeping the Black voting-age population the same. The lower court found the lead mapmaker targeted a 17 percent African American population in the district.

Much of the case relies on the lower court’s reliance on various experts who opined on the map-making and whether race was used to draw the design.

“This court should affirm the panel’s factual racial gerrymander factual finding, because it is more plausible in light of the total of the record,” Leah Aden, Legal Defense Fund senior counsel who represented the plaintiffs, told the justices.

The Supreme Court’s three liberals Wednesday intensely questioned how the state Republican lawmakers could show clear error, the standard for the justices to overrule the panel’s factual findings.

“On each expert, you take potshots and say ‘they’ve failed to do this, failed to do that,’” Justice Sonia Sotomayor told the state Republicans’ attorney.

“But we’ve never required one perfect expert to testify to all aspects of a case. But I worry that your methodology is going to suggest that what we do now is do exactly that,” Sotomayor added.

The exchanges at times sparked sparring with conservative Justice Samuel Alito, who was particularly vocal at Wednesday’s argument and seemed sympathetic to the state Republicans’ argument. 

At trial, the mapmaker testified to the panel that he did not consider race when making the changes, though he conceded examining racial data after drawing each version.

“Surely, there were good reasons to do race as a proxy for politics here … the information the map drawers had on their computer was a single presidential election year voting data and then lots of race data,” Liberal Justice Elena Kagan said.

Alito, holding his mic as Kagan spoke, jumped in a few moments later.

“Is there anything suspicious about the fact that a map drawer knows the racial demographics of the state or has available the racial demographics of the state? Haven’t we spoken about that?” Alito said.

“Yes, many times, this court has said mere awareness or consideration of race doesn’t prove racial predominance, and that would be particularly true in a state like South Carolina,” responded John Gore, the attorney representing the Republican lawmakers.

A decision in the case, Alexander v. South Carolina State Conference of the NAACP, is expected by the end of June.