Partisan splits have been three times as common this year on the N.C. Supreme Court compared to the last period when Democrats held a 4-3 advantage.

It’s a fact worth keeping in mind as the state’s highest court considers an unprecedented move. Democrats could vote to boot two new Republican members from hearing a high-profile case involving voter ID.

When Republicans swept statewide judicial races in the 2020 election, Democrats’ Supreme Court majority dropped from 6-1 to 4-3. New GOP-affiliated Justices Tamara Barringer and Phil Berger Jr. joined the court, while Republican Paul Newby unseated Democrat Cheri Beasley to become the new chief justice.

One need look back no further than 2017-18 to review the last time Democrats held a similar 4-3 edge. At that time, the court also had a Republican chief justice. In addition to Newby, current Democratic Justices Sam “Jimmy” Ervin IV, Robin Hudson, and Michael Morgan served in that configuration of the state’s highest court.

A comparison of the two courts offers enlightening data points.

The 2017-18 court produced 155 opinions over two years. This year’s court already has released 144 opinions.

The change in caseload had no impact on the rate of unanimous rulings. In 2017-18, the seven justices agreed in the decisions for 125 cases. That’s an 81% rate of unanimity. This year, 116 unanimous rulings in 144 cases yields the same 81% rate.

At the opposite end of the spectrum, the cases that produce the closest of splits — 4-3 — have featured a more noteworthy difference.

The 2017-18 court split 4-3 in 13 cases over the course of two years. That’s roughly 8% of the court’s total rulings. Just three of the 13 splits (2% of total cases) produced party-line votes.

One was the high-profile Jan. 26, 2018, decision in Cooper v. Berger. In that case, the court’s four Democratic justices killed the Republican-led General Assembly’s plan to create a new state elections and ethics board with even bipartisan membership.

But most 4-3 splits during the earlier two-year period of a slight Democratic majority did not involve party-line votes. In seven of the cases, the three Republican justices united with one Democrat — either Ervin or Morgan — to form a majority against the other Democrats. In three cases, a single Republican joined three Democrats in the majority, while one Democrat — again, either Ervin or Morgan — dissented.

Looking at 2021, the court already has split 15 times this year with a 4-3 vote. That’s 10% of the court’s total cases. Nine of those 15 (6% of the total caseload) have pitted the court’s four Democrats against its three Republicans. Among the other six cases, five have featured Morgan joining the court’s three Republicans to form a majority. In one instance, Ervin voted with the Republicans against the other Democratic justices.

The GOP-affiliated justices have voted with each other every time. That means there have been no cases this year of bipartisan splits with justices of both parties among both the majority and the dissenters. In other words, Republican justices have voted either in the majority or as a three-vote dissenting bloc.

This year’s 4-3 splits have addressed important legal issues. Morgan voted with the Republicans twice against convicted sex offenders who challenged laws mandating satellite-based monitoring. Ervin joined the Republicans to bat back a woman’s argument that she was too intoxicated to be held accountable for stealing items from a car.

Meanwhile, the court’s Democrats united against GOP colleagues in a tax ruling against the Harris Teeter grocery chain. (Barringer equated that ruling to endorsement of a state government “success tax.”) The Democratic justices also voted together against Republicans to grant a new trial for convicted murderers in a high-profile Davidson County case. It involved a baseball-bat beating death.

At some point in the coming weeks, the court will consider the fate of two state constitutional amendments approved by N.C. voters in 2018. One lowers the state’s cap on income tax rates. The other mandates photo voter identification for elections.

It’s not clear whether the case will split Republican and Democratic justices. Nor is it clear whether the case would produce a 4-3 split in any configuration.

But it’s possible that justices will not even have a full complement of seven justices to hear the case. The court is considering a motion to remove Barringer and Berger from the case against their will. That motion would require Democratic justices’ votes to succeed. They would then hold a 4-1 majority when deciding the case’s outcome.

Given the increased incidence of party-line votes this year, compared to the 2017-18 court, a vote to remove two Republican justices would be certain to raise concerns of heightened courtroom partisanship.

No one of any political persuasion should be cheering for that kind of blemish on the court’s reputation.

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