Shortly after Wisconsin voters replaced Republican Gov. Scott Walker with Democrat Tony Evers in 2018, GOP lawmakers scrambled to strip the incoming governor of power. In a special session, Republicans revoked Evers’ ability to make dozens of appointments throughout the executive branch, reducing his authority over state commissions. They hobbled incoming Democratic Attorney General Josh Kaul’s ability to represent the state in litigation. And they slashed early voting across the state in violation of a federal court order. Walker approved the power grab weeks before leaving office.

On Thursday, Circuit Judge Richard G. Niess blocked every single law the Republican legislature passed in late 2018. In his ruling, Niess held that the session was convened in violation of the state constitution, rendering the bills it produced unlawful and void. The decision vacates 82 of Walker’s last-minute appointments, restores Evers’ oversight over the executive branch, and allows Kaul to represent Wisconsin in court. But Republicans are certain to appeal the decision, where a 4–3 conservative majority may well reverse it.*

Wisconsin Republicans’ lame-duck legislative coup is, by now, a familiar story. Faced with a Democratic governor, GOP legislators decided to hobble the executive branch they’d spent years empowering under Walker. They passed a fusillade of laws that allowed Walker to make midnight appointments and barred Evers’ control over multiple state commissions. These measures transferred appointment power from the governor to the state Assembly, allowing legislators to appoint members to the Department of Corrections, the Department of Transportation, the Group Insurance Board (which oversees state benefits), the Department of Administration (which creates the state budget), and more. They also curbed executive agencies’ ability to pass regulations regarding taxes, education, elections, and health care.

GOP lawmakers also took aim at Kaul’s office, abolishing the Office of the Solicitor General and restricting Kaul’s involvement in a lawsuit brought by and against Wisconsin. Historically, the attorney general represents the state in litigation, but the new laws authorized legislative leadership to defend state laws—using private lawyers paid for by taxpayers—instead. They also forbade the attorney general from settling or withdrawing from litigation without legislative consent. This rule was designed to maintain Wisconsin’s participation in a lawsuit to kneecap the Affordable Care Act. (An additional measure curtailing early voting has already been blocked by a federal court.)

The legislature requires express permission from either a statute or the governor to call a special session. It received neither.

Evers, along with a group of civil rights advocates, filed suit in state court, alleging that the special session—and, by extension, the legislation it produced—was illegal. Niess agreed in a sharply worded opinion. Before statehood, Niess explained, colonists had “very real grievances” with “irregular legislative sessions.” To “constrain legislative overreach and safeguard the people’s liberty from irregular, capricious, precipitous, and unpredictable meetings of the Legislature,” the framers of the Wisconsin constitution adopted “a check on the Legislature’s otherwise unfettered discretion.” Under that constitution, the Assembly may only meet “at such time as shall be provided” by statute, or “unless convened by the governor in special session.”

But no statute permitted the Assembly to meet in December 2018. And “for whatever reason,” Walker failed to “exercise his constitutional authority to call a special session.” Rather, a majority of two legislative committees voted to convene the full Assembly. In total, just eight lawmakers—five representatives and three senators, all Republicans—voted to convene the December special session. The legislature then passed three sweeping bills and appointed Walker’s 82 midnight appointments.

To justify their maneuver, GOP legislators cite a statute that allows the legislature to develop a “work schedule” for its own session. By convening the Assembly, Republicans argue, lawmakers merely exercised their authority to modify their “work schedule,” calling back legislators for unfinished business. Niess disagreed. This “coiled reasoning,” he wrote, cannot mask the fact the legislature convened a session “not at a time set by law,” but “by just a few legislators on short notice.” Republicans cannot short-circuit the constitution by “creat[ing] its own authority to meet … any time at all.” The legislature requires express permission from either a statute or the governor to call a special session. It received neither, and so the actions it took ran afoul of the constitution.

Niess’ decision is hard to quibble with, but the Wisconsin Supreme Court’s current far-right majority will probably overturn it—if it gets the chance. In April, Wisconsin voters will replace an outgoing Democratic justice with either Brian Hagedorn, a controversial conservative, or Lisa Neubauer, a progressive. If Neubauer wins, the court’s 4–3 conservative majority will remain—though a Republican justice’s seat is up in 2020, giving Democrats a chance to finally flip the court.* Unless Evers can delay the appeal until after the 2020 election, which is unlikely, the current GOP majority seems poised to reverse Niess.