In a significant victory for election reform advocates, a unanimous Supreme Court upheld Arizona’s redistricting plan, which had been challenged by Republicans.

The case comes just a year after the Court’s liberals, plus Justice Kennedy, upheld the legitimacy of the Arizona Independent Redistricting Commission, which had been created by ballot initiative. That case was controversial, since the Constitution specifically requires districts created “by the legislature” of each state, not by an independently constituted commission. Justice Ginsberg, writing for the Court, said that the “people’s legislative power” was close enough. Not surprisingly, the Court’s more literalist wing was outraged.

It’s perhaps surprising, then, that today’s case, Harris v. Arizona Independent Redistricting Commission, was decided 8-0. On the one hand, the case may represent a consensus on at least some aspects of election law—and is thus very good news for electoral reform activists. On the other hand, since it basically defers to a state decision, it’s not a robust test case.

The facts of the case are straightforward. Despite being independent, the five-person Redistricting Commission is still divided among Democrats, Republicans, and ostensible independents: two, two, and one, respectively, with intricate appointment procedures. In April 2012, the two Democrats and one independent modified three districts, and the two Republicans voted against, arguing that the new plan favored Democrats.

Contrary to what you might expect, however, the Supreme Court has never said that partisan gerrymandering is against the law. If the districts disadvantage minorities, a redistricting plan might violate what’s left of the Voting Rights Act. And if they contain wildly different populations, the plan might violate the Equal Protection Clause of the Constitution. But it’s not actually against the law to be craven, manipulative, and duplicitous.

Given that, it’s not surprising that the petitioners lost—though it is surprising that they lost unanimously.

First, while Republicans alleged that the plan was designed to benefit Democrats, there was significant evidence in the record that showed it was actually designed to meet the requirements of the Voting Rights Act. (The plan was ratified before the Supreme Court eviscerated the Voting Rights Act in Shelby County v. Holder.) In particular, it seems those concerns swayed the one independent member of the commission.

Second, the population deviations in the Arizona plan were around 4 percent. That’s well below the 10 percent threshold the Court has adopted when applying the Equal Protection clause. True, that variation was all on one side—Republican-leading districts were generally more populous than Democrat-leaning ones. But that’s not necessarily illegal, and anyway the variation can be explained by the need for the plan to conform with the Voting Rights Act.

Third, while part of the Voting Rights Act was held unconstitutional in 2013, in Shelby County, that doesn’t corrupt Arizona’s motives in complying with it back in 2012. At the time, the redistricting commission was trying to obey the law, not stack the decks.

Does this unanimous decision represent a new dawn for election reform? Not quite.

To be sure, the unanimity does suggest that the redistricting commission is now a fait accompli. No one dissented, or even wrote a separate concurrence, to protest its existence. One wonders if Justice Scalia might have done so, but Chief Justice Roberts, certainly, is not likely to question one of the Court’s recent precedents; he is particularly committed to the legitimacy of the Court and its decisions. On the contrary, he has now joined an opinion upholding the commission’s decision—and one that tends to favor Democrats.

On the other hand, the thing about unanimous decisions is that they tend to signal, at least retroactively, that these cases were relatively easy ones. They are precisely not the ones that indicate a lot of movement on key issues.

For example, while the Religious Right cheered a religious freedom case decided unanimously by the Supreme Court last year, the reason it was unanimous is that it was an old school, religious-liberty-as-shield-against-the-government case. That case involved a prison inmate wanting to grow a half-inch beard; no third parties were involved, no harm was done, and the prison’s safety rationales were ludicrous. That’s why it was uncontroversial.

While much of the Court may not like the context of the commission’s decision, that question is now settled, and what’s left is a far-fetched constitutional claim against a reasonable, and well-documented, state agency decision.

And, as usual in unanimous decisions, Justice Breyer’s opinion tends toward the minimalistic. No wild statements of law or policy here; this opinion was generated to build consensus, and it did so.

Still, this is a significant step forward for election reform. The Arizona Redistricting Commission is an innovative idea, with an elaborate attempt to minimize partisanship and increase accountability. There were constitutional grumblings last year when the Supreme Court decided “the legislature” could also mean “the people,” but as a matter of policy, the commission is an important model for how to improve the messy, dirty redistricting process. On it ride many hopes of democracy advocates.

And today, it won a ringing endorsement from a unanimous court.