Black voters challenging Georgia’s method of electing members to the state’s public service commission scored a preliminary US supreme court order in their favor late Friday.

The decision came after conflicting rulings from lower courts earlier this month, offering up a rare example of the supreme court’s 6-3 conservative majority’s siding with voters over state officials.

Earlier this month, a federal district judge found that the current system gave Black residents’ votes less weight. Each of the commission’s five seats hold jurisdiction over a specific district, but each seatholder is elected in a statewide race that dilutes Black voters’ power, said that ruling, which came from Trump White House-appointed judge Steven Grimberg.

Grimberg ordered the postponement of a November election for two commissioners’ seats to allow the state legislature the time to create a new system for electing commissioners, granting a request from a group of voters challenging the system.

However, last week, the federal 11th circuit court of appeals temporarily halted Grimberg’s ruling, citing the “Purcell principle”, which discourages courts from changing election rules immediately before an election.

The supreme court on Friday reinstated the Grimberg ruling, with the plaintiffs citing testimony from numerous experts who found the current Georgia public service commission election system to be discriminatory against Black voters.

Political data analyst Bernard Fraga, who focuses on the behavior of voting within communities, testified that statewide voting lets Georgia’s majority white population drown out votes coming from districts with mostly Black residents.

“And, because elections are staggered, a minority group has less of an opportunity to concentrate its voting strength behind a candidate of choice,” Fraga said, according to the ruling.

The ruling also cited the testimony of a former employee at the US justice department’s civil rights division, Stephen Popick.

He said his study on voting behavior in Georgia between 2012 and 2020 showed “voter polarization” between Black and white voters, and the latter’s candidate always won even though Black voters all got behind the same leader as a group.

Plaintiffs attorney Nico Martinez on Saturday told the Guardian he is “confident the district court’s well-reasoned decision will ultimately be upheld” as the case continues playing out in the 11th circuit, which could still block Grimberg’s ruling on other grounds, paving the way again for the November election date.

“We are pleased that the supreme court took this important step to ensure that this November’s [public service commission] elections are not held using a method that unlawfully dilutes the votes of millions of Black citizens in Georgia,” said Martinez, a partner at the law firm Bartlit Beck.