This opinion piece was first published in The Wall Street Journal.

The Supreme Court considers on Wednesday whether the Constitution’s Elections Clause means what it says—that “the times, places and manner of holding elections for senators and representatives, shall be prescribed in each state by the legislature thereof.” That question arises from a litigation blitz seeking to override state election laws. Unless the justices get the answer right, elections for Congress and president could become a free-for-all with judges being the ultimate deciders.

At issue in Moore v. Harper is North Carolina’s congressional map. In 2021 the state legislature—the General Assembly—enacted a redistricting plan. Lawmakers expressly rejected partisan considerations in drawing district lines. Nonetheless, groups aligned with the Democratic Party sued, arguing that the map was a partisan gerrymander and violated the state constitution.

The precise nature of that violation is an interesting question. Unlike some state constitutions, North Carolina’s doesn’t forbid partisan redistricting. Lacking any textual hook for their claim, the challengers cited a potpourri of state constitutional clauses, including ones guaranteeing “free elections,” equal protection and even free speech. The North Carolina Supreme Court ruled in their favor, despite having rejected a similar claim a few years earlier, and ultimately a court-imposed congressional map was used for this year’s elections.

The U.S. Supreme Court’s task in Moore is straightforward. The Elections Clause directs “the legislature” to regulate congressional elections, which includes drawing district maps. State courts aren’t part of the legislative process, and thus the North Carolina Supreme Court was obligated to uphold the General Assembly’s map.

It really is that simple. Many other constitutional clauses refer to a “state,” but the Elections Clause singles out a state “legislature.” In so doing, it conveys a unique legislative power to make a type of federal law. Like all federal laws, these can’t be trumped by state constitutional provisions. State courts have the power to interpret election regulations, but they can’t override the legislature’s handiwork unless it conflicts with the U.S. Constitution or a statute enacted by Congress.

The historical record of litigation involving federal election laws is straightforward, too. Of the bushels of briefs supporting the Moore plaintiffs, not one identifies a state-court decision striking down a law governing federal elections until 70 years after the founding. When disputes arose during the Civil War over whether state legislatures could permit absent Union soldiers to vote by mail despite in-person voting requirements in state constitutions, state supreme courts split on the question. The U.S. Supreme Court never heard an appeal in these cases.

Not until this century did state judges presume to override federal-election legislation when it violated their notions of how best to conduct “free,” “fair” or “equal” elections, in litigation brought mostly by Democrats. The Pennsylvania Supreme Court, for instance, in 2018 imposed its own congressional redistricting plan (drawn in secret) and held in 2020 that a Tuesday statutory ballot-receipt deadline could become a Friday deadline, viewing Friday as more “free” and “equal” than Tuesday.

The Moore plaintiffs cite Supreme Court precedents that read “the legislature” to mean “the state’s lawmaking process.” In Smiley v. Holm (1932), the justices held that a congressional redistricting plan didn’t take legal effect without the governor’s signature because the governor had “a part in the making of state laws” through the veto power. In Arizona State Legislature v. Arizona Independent Redistricting Commission (2015), the court approved of an independent redistricting commission adopted in a ballot initiative by the people as citizen-legislators.

Yet neither of these cases read the word “legislature” as a mere synonym for “state.” While the former term may be broader than state houses and senates, it is narrow enough to encompass only those people and institutions involved in making laws. The job of North Carolina’s courts is to interpret the laws; they have no role in the legislative process.

The Moore plaintiffs also argue that Election Clause legislation is subject to state-court review because Congress is subject to federal judicial review when it acts under the Elections Clause to “make or alter” congressional election laws. That’s a faulty analogy. Acts of Congress are always subject to review for compliance with the U.S. Constitution, but never under state constitutions. The U.S. Constitution’s Supremacy Clause privileges the Constitution over federal statutes and federal statutes over all state laws, including state constitutions. Importantly, that clause defines “the laws of the United States” as those “made in pursuance” of “this Constitution,” which includes the Elections Clause and its delegation to “the Legislature” of each state. By logical consequence, the U.S. Constitution constrains state legislatures exercising their authority under the Elections Clause, but state constitutions don’t.

The Moore plaintiffs also make political arguments. They contend that a plain-text reading of the Elections Clause would be “damaging for American democracy.” Legal commentators pillory state legislatures as partisan bodies and lionize state courts as guardians of democracy—even in states like North Carolina and Pennsylvania, where judges are selected in partisan elections. They also insist that it would jeopardize minority voting rights, which are protected under federal law that won’t be affected by Moore.

The core of American democracy is rule by the people through their elected representatives—not by judges, whether elected or appointed. Legislation can be good, and court decisions can be bad, as easily as the reverse. No one would contend that legislation permitting deployed Union soldiers to vote in federal elections was harmful to democracy, yet fidelity to the Elections Clause made that possible in some states while a theory of state-court supremacy disfranchised them in others. Those who loudly profess the need to “save” democracy are dead-set against it when it stands in the way of their partisan objectives.

Mr. Rivkin served at the Justice Department and the White House Counsel’s Office in the Reagan and George H.W. Bush administrations. Mr. Grossman is a senior legal fellow at the Buckeye Institute. Both practice appellate and constitutional law in Washington. They filed an amicus brief on behalf of state legislators supporting Moore challengers.