LANSING — The Michigan Supreme Court on Thursday dismissed a lawsuit against the state’s new independent redistricting commission that alleged new maps illegally dilute the power of Black voters.

Plaintiffs, including state lawmakers who are part of the Legislature’s Detroit Caucus, failed to prove a violation of the 1965 Voting Rights Act, justices wrote in a 4-3 opinion, rejecting the first of several legal challenges against the maps that are set to take effect next month.

In oral arguments last week, an attorney for plaintiffs argued new legislative and congressional districts drawn by the independent commission would significantly reduce the number of Black elected officials in Michigan.

Michigan currently has 17 majority-Black districts — two in Congress, five in the state Senate and 10 in the state House. But in the 10 proposed maps released by the commission last month, only one district would have a voting age population of more than 50 percent African-Americans.

But high court justices, including three of four Democratic nominees, said a reduction in majority-Black districts alone is not a violation of the Voting Rights Act, which guarantees a chance for minority voters to elect candidates of their choice.

The court cited expert analysis prepared for the commission suggesting “significant white crossover voting for Black-preferred candidates … had the effect of affording Black voters an equal opportunity to elect representatives of their choice even in the absence of 50%+ majority-minority districts.”

That evidence of “white crossover voting” went “unrebutted” by the plaintiffs, according to the majority opinion.

Democratic nominees Chief Justice Bridget McCormack, Megan Cavanagh and Elizabeth Welch were joined in their dismissal by Justice Elizabeth Clement, a Republican nominee.

The justices said they were bound by U.S. Supreme Court precedent and were comfortable making an unusually quick decision because an attorney for plaintiffs conceded he had no additional evidence to present in the case beyond the number of majority-minority districts created by the commission.

Appearing last week before the state’s highest court, attorney Nabih Ayad argued the commission made African Americans a “sacrificial lamb” in the redistricting process, calling the new maps “not fair.”

Republican-nominated justices Brian Zahra and David Viviano, along with Democratic nominee Richard Bernstein, signed a dissent disagreeing with the speed of Thursday’s decision, which they called premature.

“Instead of dismissing the case without any analysis of whether plaintiffs have stated a claim or any opportunity for further factual development if they have stated a claim, we would appoint an independent expert to assist the Court in assessing the evidence and factual assertions,” they wrote in the dissent.

Thursday’s dismissal is the first resolution in a series of lawsuits challenging the work of the Michigan Independent Citizens Redistricting Commission. Voters created the 13-member panel as part of a constitutional amendment to the state constitution in 2018, replacing a process that allowed the party in charge of the Michigan Legislature to redraw legislative boundaries every 10 years after the decennial census.

The largely secretive process created districts that a panel of judges in 2019 called a “gerrymander of historical proportions.”

At least two other lawsuits challenge district boundaries created by the redistricting commission, including a federal complaint by Republican lawmakers who claim new congressional districts “fragment counties, townships, and municipalities” without a necessary reason.

Another lawsuit filed with the Michigan Supreme Court this week by voting rights advocacy groups alleges newly-created state House maps are unfair to Democrats.

Absent court intervention, the new maps will be used in primary and general elections later this year for Congress and the Michigan Legislature.

Bridge reporter Sergio Martínez-Beltrán contributed