Last week, a three-judge district court unanimously held that twenty-seven Michigan state house, state senate, and congressional districts are unconstitutional partisan gerrymanders. The consequences of the decision are important. If it’s upheld, Michigan will have fair district maps in 2020 for the first time in two decades. Just as striking as the decision’s effects, though, is the familiarity of its reasoning. In almost every respect, the decision echoes earlier court rulings striking down districts in Maryland, North Carolina, Pennsylvania, and Wisconsin. The decision is thus further proof that, while the Supreme Court continues to debate the issue, the lower courts have found a way to identify—and invalidate—extreme gerrymanders.

Take the “three-part framework” endorsed by the Michigan court, which requires showings of “(1) discriminatory partisan intent, (2) discriminatory partisan effects, and (3) causation and/or a lack of justification.” This is the same test adopted by three previous federal courts. As the Michigan court noted (quoting an earlier opinion by an Ohio court), “federal courts have ‘converged considerably on common ground in establishing standards for determining whether a partisan gerrymander is unconstitutional.’”

Or consider the district-specific evidence the Michigan court analyzed. In its decision last year in Gill v. Whitford, the Supreme Court held that a plaintiff bringing a claim of partisan vote dilution must show that her own district was unnecessarily cracked or packed. A fair inference from the Court’s decision is that, to establish liability, a plaintiff must also prove that her district was intentionally cracked or packed. Consistent with both Whitford’s holding and its implication, the Michigan court carefully explained that twenty-seven districts cracked or packed Democratic voters, that they did so deliberately, and that this cracking or packing could have been avoided. The Michigan court also ruled that plaintiffs lacked standing in seven challenged districts because their votes continued to be diluted in the alternative maps they presented. And again, this meticulous district-by-district examination is exactly the same as that conducted by other federal courts: most notably, by the North Carolina court in a case now pending before the Supreme Court.

The remarkable judicial convergence extends to the plan-wide evidence accepted by the Michigan court. The court found that all three Michigan plans have exhibited staggering levels of partisan asymmetry. The congressional map, for example, has been “more extreme than 95% of previous plans in states with more than six seats over the past 45 years.” The court also found that these biases are highly durable. Under each map, “it would take an extraordinarily strong showing by Democrats to unseat the Republican majority.” The court found as well that all three plans are more skewed than thousands of alternative maps generated randomly by a computer algorithm without using election results. For instance, the actual congressional plan has nine Republican-leaning districts, while “the vast majority of [simulated congressional maps] created 7 Republican congressional districts and 7 Democratic congressional districts.”

Once more, this is precisely the same plan-wide evidence—bearing on precisely the same elements of discriminatory effect and lack of justification—considered by earlier federal courts. And once more, the Michigan court clarified that it was not constitutionalizing the plan-wide methods and metrics on which it relied. Rather, the “robust social science” was simply “evidence” that helped to prove the plaintiffs’ “allegation that the Enacted Plan violated their constitutional rights.”

The Michigan court added one more notable comment. Before it began its analysis, it remarked that “judges—and justices—must act in accordance with their obligation to vindicate the constitutional rights of those harmed by partisan gerrymandering.” Federal judges are increasingly complying with this duty, based on the same legal framework and the same factual evidence. The question now is whether the justices will follow the judges’ lead.