The U.S. Supreme Court has tossed out a lower court ruling that would have forced a substantial redrawing of Michigan’s congressional and state legislative voting maps in a bid to give Republicans less of an edge.

The one-sentence order issued Monday was expected after the high court’s June 27 decision that upheld a Republican-drawn congressional map in North Carolina and Democratic-drawn voting lines in Maryland.

In the 5-4 ruling, Chief Justice John Roberts wrote for the conservative majority that gerrymander claims involve "political questions beyond the reach of the federal courts."

The decision effectively insulated gerrymanders from federal court challenges.

"Federal judges have no license to reallocate political power between the two major political parties...," Roberts wrote, arguing letting them do so would be an "unprecedented expansion of judicial power."

The Supreme Court’s order doesn’t directly affect the independent commission Michigan voters approved last year to draw voting lines for 2022 and beyond. A separate lawsuit by Republican officials is challenging the commission's constitutionality.

In April 2018, a three-judge panel had ruled that Michigan had to redraw legislative and congressional districts for the 2020 election because current maps drawn by Republicans represent a political gerrymander “of historical proportions."

The 2011 redistricting plan's “predominate purpose ... was to subordinate the interests of Democratic voters and entrench Republicans in power,” said the unanimous decision written by U.S. Circuit Judge Eric Clay, an appointee of Democratic President Bill Clinton.

Joining Clay was Detroit U.S. District Judge Denise Page Hood, who was also appointed by Clinton, and Grand Rapids U.S. District Judge Gordon Quist, an appointee of Republican former President George H.W. Bush.

If allowed to stand, the blockbuster lower court ruling would have had severe implications for the 2020 elections.

The lower court judges had ordered the redrawing of at least nine of Michigan's 14 congressional districts and 15 state House districts, including more that would have been affected by political boundary shifts. But they also would have prompted the realignment of 10 state Senate districts and many others touching them and forced their senators into special elections in 2020 — halfway through their four-year terms and before their normal re-election bids in 2022.

If state officials had not finalized new maps by a certain deadline. the federal panel court could have drawn new boundaries itself or appointed a special master to do so.

The lawsuit was filed on behalf of the League of Women Voters of Michigan and some aggrieved Democrats. The complaint was eventually narrowed down to target 34 of the state’s 162 congressional and legislative districts that would need to be redrawn, along with any bordering districts they impact.

The new Supreme Court order follows a similar move that sealed a win for Ohio Republicans on their gerrymandered congressional voting map.

The order has no direct effect on a separate lawsuit that seeks to overturn a voter-approved independent redistricting commission for Michigan's elections in 2022 and beyond. In September, a Grand Rapids federal judge consolidated two GOP suits against the redistricting commission.

The Michigan Republican Party has argued the commissioner selection process violates the GOP’s freedom of association rights by precluding parties from picking their own representatives to serve on the panel. The conservative Michigan Freedom Fund estimates the rules could disqualify more than a half-million Michigan residents from the commission.

Democratic Attorney General Dana Nessel's office, representing Secretary of State Jocelyn Benson, has argued plaintiffs aren't precluded from the commission because of political relationships but due to conflicts of interest. It is similar to excluding people from jury duty for knowing people in a legal proceeding and thus having a stake in the case, Nessel's office said,

Bloomberg News contributed