Gov. Roy Cooper and Attorney General Josh Stein blame partisanship for the N.C. Supreme Court’s decision to reject their latest brief in a case dealing with election maps.

Both men should know better. Their brief ran afoul of the court’s rules.

Most people don’t need to know the details of state Supreme Court operations. But we ought to expect more from Stein, who has served as state government’s top lawyer for more than six years. The same could be said for Cooper, who served as N.C. attorney general for 16 years before moving to the Executive Mansion.

The state’s highest court scheduled a rare rehearing this week in Harper v. Hall. That’s a case in which critics of North Carolina’s Republican-led General Assembly challenged maps state lawmakers drew for congressional and legislative elections.

In December, little more than a month after voters replaced two Democratic state Supreme Court justices with Republicans, the outgoing court’s 4-3 Democratic majority ruled against GOP lawmakers. Democratic justices agreed with a trial court ruling tossing out a Republican-drawn congressional map. High-court Democrats also went beyond the trial court’s decision. Justices tossed out the state Senate map used for the 2022 election.

Legislative leaders believed the court made constitutional errors. They followed established court procedures and asked the new Supreme Court to rehear the case. Now with a 5-2 Republican majority, the court agreed.

Article II, Section 22(5) of the state constitution expressly removes the governor from any role in North Carolina’s election mapmaking process. Nor does the attorney general hold any power to insert himself into redistricting decisions.

Yet Cooper and Stein filed a joint amicus, or friend-of-the-court, brief during the Harper v. Hall case’s initial appearance before the Supreme Court. Justices accepted the brief without dissent. The governor and attorney general, both Democrats, spelled out their concerns about Republican lawmakers’ actions during the electoral mapmaking process.

On March 3, one month after the state Supreme Court granted a rehearing in the case, Cooper and Stein filed a motion to submit a new brief in the case. Six days later, the court denied that motion.

“With each passing day, this partisan Supreme Court shows that it cares only about the views of Republican legislators,” Cooper tweeted from his official account. “That comes at the cost of voting rights, school funding, and — ultimately — our democracy.”

Stein chimed in. “The governor and the attorney general are elected statewide by the people of North Carolina to uphold and enforce the North Carolina Constitution,” he tweeted. “It is shocking that the North Carolina Supreme Court silenced the voices of the people’s chosen leaders on an issue so critical to our democracy.”

Yet the two men ignored key facts.

First, the Supreme Court order rejecting their brief was unanimous. The two Democratic justices offered no dissenting remarks.

Second, the order referenced Rule 31(d) of the state’s Rules of Appellate Procedure. That rule dictates the court’s procedure when it grants a rehearing. “The case will be reconsidered solely upon the record on appeal, the petition to rehear, new briefs of both parties, and the oral argument if one has been ordered by the court.”

In other words, no friend-of-the-court briefs. At the same time the state Supreme Court rejected Cooper and Stein’s motion, justices rejected a separate brief from the Brennan Center for Justice at New York University’s law school. The orders are nearly identical.

The two men who have led North Carolina’s Department of Justice for more than 20 years should have known Rule 31(d). At the very least, they should have read the rule after seeing the court’s order. It might have saved them from tweeting baseless partisan accusations.

Perhaps Cooper and Stein’s defenders are not satisfied. They might respond that the Republican-dominated Supreme Court applied the rules selectively. In their view, the state’s highest court might have bent the rules to accept a similar brief from a GOP-backed group.

Not so fast.

In addition to Harper v. Hall, the state Supreme Court scheduled a rehearing this week in Holmes v. Moore. That’s the case involving a legal challenge to North Carolina’s 2018 voter identification law.

Ten days before Cooper and Stein filed their motion in Harper v. Hall, the state Supreme Court issued an order denying a motion to file a new friend-of-the-court brief in the voter ID case.

The group that sought permission to add new arguments to the legal debate? The N.C. Republican Party. Not a single Republican justice offered a dissenting viewpoint.

The high court applied Rule 31(d) to both cases. One ruling affected the state GOP. The other affected two top Democratic politicians.

Cooper and Stein are lawyers. They know the legal process features plenty of rules. More than most lawyers, they should know the rules for dealing with the state’s highest court.

It’s a shame they ignored the rules and the facts of their case. They focused instead on partisan posturing.

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