The Supreme Court declined to strike down several Texas legislative and congressional districts on grounds of discrimination against Hispanic voters, in a blow to activists who want the courts to take a tough line against racial gerrymandering.

In a 5-4 ruling issued Monday in the Abbott v. Perez case, the court’s conservative justices found that a lower court “erred” in its findings that several districts were racially gerrymandered, and left them in place. Just one district at issue in the case, they found, was an impermissible racial gerrymander.

The four liberals, however, disagreed, with a scathing dissent written by Justice Sonia Sotomayor. The ruling, Sotomayor wrote, “comes at serious costs to our democracy,” and means that “minority voters in Texas” will remain underrepresented despite “undeniable proof of intentional discrimination” in map-drawing. “The fundamental right to vote is too precious to be disregarded in this manner,” Sotomayor writes.

But in an opinion written by Justice Sam Alito, the court’s conservatives — including Justice Anthony Kennedy, often a swing vote in matters of gerrymandering — did not agree.

The ruling is complex, as is the chain of events that led to this case being before the Supreme Court in the first place: There have been multiple proposed maps and court rulings about those maps in Texas over the past decades.

The gist, however, is that the conservative justices thought the challengers did not sufficiently show that these particular modified versions of Texas’s maps were “tainted” by “discriminatory intent” — even if earlier, largely similar versions of the maps had been tainted. Furthermore, the justices refused to strike down two state legislative and one congressional district on grounds of alleged discrimination in effect (rather than intent).

The big political takeaway, though, seems to be that the majority on the Supreme Court wants to set a high bar before federal courts can step in and block states’ district maps on racial grounds.

What the Texas gerrymandering Abbott v. Perez decision was about

The Supreme Court has never yet seen fit to intervene and block a state map on grounds of partisan gerrymandering — drawing district lines to benefit one party over another. And that trend continued last week, when the justices declined to rule on the merits in the Gill v. Whitford case.

Racial gerrymandering, however, is different — there’s ample precedent for the courts stepping in to stop it. For decades, the courts have held that the Equal Protection Clause of the 14th Amendment forbids gerrymandering on racial grounds. The Voting Rights Act of 1965, meanwhile, requires states to consider the impact on racial minority representation when redrawing districts.

In 2011, the Republican-controlled Texas state legislature redrew the state’s congressional and legislative maps, in a way that greatly helped the GOP. Very quickly, lawsuits were filed claiming that the maps discriminated against Hispanic voters.

That’s where things start to get complicated. Those 2011 maps were blocked by the courts. Then, federal judges in Texas proposed a new placeholder map which would be completely different. But then, the Supreme Court ruled that the placeholder map had to largely resemble the legislature’s original map.

Federal judges in Texas complied — and then the legislature passed the map those judges created, with only minor changes, into law in 2013. Finally, last year, federal judges in Texas ruled that parts of this map was racially discriminatory too, and Gov. Greg Abbott (R) appealed to the Supreme Court.

Justice Alito’s opinion relied on this complex chain of custody for the map in rejecting most of the racial gerrymandering claims. The plaintiffs had argued that Texas legislature of 2011 drew up a map with discriminatory intent, and that they could prove it. However, Alito writes, the map that’s in place now is a different one, that had gone through the courts and then the legislature again. He concludes that it was up to the plaintiffs to prove that the Texas legislature of 2013 “acted in bad faith and engaged in intentional discrimination” — and that “the evidence in the record is plainly insufficient” to prove that.

After that, the justices examined four particular districts that the lower court had ruled should be struck down on racial gerrymandering grounds. For three of them, the lower court claimed they were discriminatory in effect by diluting minority votes (without showing intentional discrimination). But Alito and the conservatives disagree, concluding they haven’t sufficiently proved discrimination.

Then there is the 90th District of the Texas state house, which was redrawn in 2013 on specifically racial grounds. (The legislature went through various versions of it, in which they moved Hispanic or black voters in or out.) The conservatives find that this was in fact an “impermissible racial gerrymander,” and that the state didn’t sufficiently argue that it was narrowly tailored.

Justice Sotomayor’s dissent in Abbott v. Perez

Yet Justice Sotomayor and the liberals were unconvinced by all this, and made it clear in a dissent that they thought the majority went “out of its way” to try to guarantee Texas “continued use of much of its discriminatory maps,” at “serious costs to our democracy.”

Sotomayor disputed Alito’s claim that the 2013 Texas legislature maps were in the clear because there was little direct evidence of discrimination in their crafting. She agrees with the lower court judges that there was “substantial evidence” that the new maps were adopted “to insulate (and thus continue to benefit from) the discriminatory taint of its 2011 maps.” She also disputes Alito’s analysis that discrimination in effect wasn’t sufficiently proven in three of the four remaining districts.

Beyond the technical disputes about which map in which year and what’s going in which district, though, the bigger picture is that the court is divided on what evidence they think is sufficient to prove racial gerrymandering — and how aggressively they should step in to try and block racial gerrymandering.

Sotomayor writes that voters’ rights to equal participation “mean little” if “courts do not remain vigilant in curbing States’ efforts to undermine the ability of minority voters to meaningfully exercise that right.” The majority, she says, “does great damage to that right of equal opportunity” because it “refuses its enforcement” — all for the purpose, she says, of letting Texas “use electoral maps that, in design and effect, burden the rights of minority voters.”

That, it seems, is where we are. The four liberals want the courts to take a more active role at protecting racial minorities’ representation in the redistricting process. But the five conservatives want to set a high bar for when the courts should step in to strike down a state map on racial grounds — and they’re in the majority.