Perhaps the political left should have listened to Clarence Thomas in Moore v. Harper.

A U.S. Supreme Court decision issued three days after that major redistricting ruling helps explain why.

In Moore v. Harper, North Carolina’s Republican legislative leaders had asked the high court to reverse a 2022 ruling from the N.C. Supreme Court. Lawmakers argued that state courts had concocted a dubious interpretation of the state constitution to strike down lawmakers’ preferred congressional election map. The court had invented a state constitutional ban against overly partisan gerrymandering.

The U.S. Supreme Court rejected lawmakers’ plea on June 27. A 6-3 decision authored by Chief Justice John Roberts affirmed the N.C. Supreme Court’s right to issue its own election map ruling.

Yet the high court’s decision did not amount to the clear loss for N.C Republicans that major media outlets reported.

A political shift on the N.C. Supreme Court after the 2022 elections had produced a new election map ruling in April. The state’s highest court threw out its challenged 2022 decision. Justices disavowed the dubious legal reasoning that underpinned the earlier decision.

Because of the state Supreme Court’s reversal, legislators are free to draw new election maps this year. Critics cannot challenge those maps in state court under claims of partisan gerrymandering.

The April state Supreme Court decision gave legislative leaders the outcome they wanted, regardless of the U.S. Supreme Court’s Moore v. Harper ruling.

That was the key point Thomas made in his dissent. The longest-serving member of the high court argued that his colleagues should have dismissed the case as “indisputably moot.”

“This is a straightforward case of mootness,” Thomas explained. “The federal defense no longer makes any difference to this case — whether we agree with the defense, disagree with it, or say nothing at all, the final judgment in this litigation will be exactly the same. The majority does not seriously contest that fact.”

Yet Thomas’ argument secured only three of the court’s nine votes. The three clearly left-of-center justices all supported Roberts’ majority opinion.

That support could come back to bite left-wing partisans.

Beyond the N.C. dispute, the Moore v. Harper majority staked out new constitutional ground.

State courts can review state legislatures’ election maps and other legislation linked to the U.S. Constitution’s Elections Clause. But state courts do not have “free rein.” The top federal court will step in when state courts overstep their authority.

“In interpreting state law in this area, state courts may not so exceed the bounds of ordinary judicial review as to unconstitutionally intrude upon the role specifically reserved to state legislatures by Article I, Section 4, of the Federal Constitution,” Roberts explained.

While the Moore majority technically affirmed the N.C. Supreme Court’s 2022 decision, Roberts stated clearly that justices “decline to address” whether the state court “strayed beyond the limits” of acceptable behavior.

Three days after Moore v. Harper, the Supreme Court addressed an Ohio case, Huffman v. Neiman. In that dispute, Ohio’s Republican legislative leaders challenged their state Supreme Court’s decision to toss a congressional election map.

Justices in Washington could have rejected the Huffman case. Or they could have affirmed the Ohio court’s ruling, pointing toward the still-fresh Moore v. Harper decision.

Instead the high court accepted the Huffman case, vacated the state ruling, and sent the case back to Columbus for reconsideration. It’s clear at least some justices believe the Ohio court botched its decision. Moore v. Harper confirmed that the U.S. Supreme Court could tell a state court not to “exceed the bounds of ordinary judicial review.”

Unlike North Carolina, Ohio uses a redistricting commission to draw election maps. Ohio lawmakers argued that the state’s top court rejected the commission’s congressional map because it failed to guarantee six Democratic victories. “It also dictated the vote share of the Democratic-leaning districts, concluding that Democrats were not really favored to win districts with Democratic vote shares of 52.15%, 51.04%, and 50.23%,” according to Ohio legislators’ court filings.

It’s unclear whether Moore v. Harper will prompt the Ohio Supreme Court to reassess its earlier ruling. It’s also uncertain whether the U.S. Supreme Court would consider the Ohio dispute again.

But top courts in North Carolina, Ohio, and the rest of the country are now on notice. Federal courts will step in when they believe state courts have intruded on legislators’ proper roles in drawing congressional election maps.

Given the court’s current composition, increased federal involvement will offer little comfort to the political left. Had their favorite justices sided with Thomas in Moore v. Harper, future court battles over congressional maps might have taken a different turn.

Mitch Kokai is senior political analyst for the John Locke Foundation.