THE SUPREME COURT’S weirdly busy October brings to mind an old Cadillac commercial showing a sedan gliding silently down the highway, driver calm and confident in a hermetic, leather-appointed cabin, while the announcer intones, “quietly doing things very well.” Whether the justices are doing their jobs well depends on your point of view. But there is no disputing that they have been doing their most consequential work in uncharacteristic silence in recent weeks. The justices' moves on gay marriage, abortion and voting rights have been delivered all but wordlessly, as Dahlia Lithwick of Slate recounts. The notable exception to the rule is Ruth Bader Ginsburg, the justice who refused to hold her tongue over the weekend, when six of her colleagues permitted Texas to enforce its new photo identification law in the November elections. The Court's announcement came down at the ungodly hour of 5am on Saturday. It followed a federal district court decision on October 9th that the Texas law was discriminatory in both intent and effect and “constitutes a poll tax”—a ruling that was stayed by the Fifth Circuit Court on October 11th. The stay prompted an emergency appeal to the Supreme Court via Antonin Scalia, the justice assigned to the Fifth Circuit. The six justices who denied the request to lift the stay before dawn on October 18th were mum as to why; they released no reasoning for the decision, which effectively gives Texas's questionable voter law a pass. But Justice Ginsburg and her clerks apparently ordered pizza and downed some Red Bull on Friday evening, pulling an all-nighter to compose a six-page dissent, which Justices Sonia Sotomayor and Elena Kagan joined. (Rick Hasen asks why Justice Stephen Breyer, the fourth liberal justice, did not sign on to the dissent; one strong possibility is that he was asleep.)

Octogenarian Supreme Court justices are not known for burning the midnight oil, but Justice Ginsburg had an unusually good reason to do so in Veasey v Perry. The Texas law she opposed is a transparent attempt to help Republican candidates by keeping racial minorities, who vote overwhelmingly for Democrats, home on Election Day. In the words of the trial judge, the law "creates an unconstitutional burden on the right to vote, has an impermissible discriminatory effect against Hispanics and African-Americans, and was imposed with an unconstitutional discriminatory purpose." Justice Ginsburg's wee-hours dissent drew on the district court's ruling to issue a scathing rebuke to the Fifth Circuit and, by implication, to the six justices who refused to lift the Fifth Circuit's stay. "In light of the 'seismic demographic shift' in Texas between 2000 and 2010, making Texas a 'majority-minority state,' " Justice Ginsburg wrote, "the District Court observed that the Texas Legislature and Governor had an evident incentive to 'gain partisan advantage by suppressing' the 'votes of African-Americans and Latinos.' ”

Justice Ginsburg also criticised the law's defenders who claim it is necessary to fight voter fraud: "Texas did not begin to demonstrate that the Bill’s discriminatory features were necessary to prevent fraud or to increase public confidence in the electoral process." The upshot is disturbing: by refusing to act, the Supreme Court majority is allowing a law to take effect that "may prevent more than 600,000 registered Texas voters (about 4.5% of all registered voters) from voting in person for lack of compliant identification...A sharply disproportionate percentage of those voters are African-American or Hispanic."

What was the majority's reasoning for deferring to the Fifth Circuit, and by extension to Rick Perry, the governor of Texas? We don't know; they didn't tell us. The rationale probably has to do with Purcell v Gonzalez, a 2006 case in which the Court decided that courts should be wary of changing voting rules too close to an election. But Purcell does not lay down an ironclad rule against last-minute changes. And as Rick Hasen writes, "[i]t appears to be unprecedented to let a law that was deemed racially discriminatory go into effect simply to avoid the risk of voter confusion and election administration inefficiency." If the six justices voting to let Texas law take effect thought that voter confusion was more worrisome than racial discrimination, they should have put that reasoning down on paper.

John Rawls, an influential political philosopher who died in 2002, described the Supreme Court as an “exemplar of public reason”, a tribunal that accounts for its decisions with reasoned reference to the laws and traditions of the country. “It is the only branch of government,” Mr Rawls wrote, “that is visibly on its face the creature of that reason and of that reason alone”:

To say that the court is the exemplar of public reason also means that it is the task of the justices to try to develop and express in their reasoned opinions the best interpretation of the constitution they can, using their knowledge of what the constitution and constitutional precedents require.

Echoing Kant, for whom the “publicity” of public decisions is a key component of a constitutional republic and is, indeed, the “transcendental principle of public right”, Rawls insisted that “the court’s role...is part of the publicity of reason” to which citizens should enjoy full and unfettered access. Normally the justices acquit themselves quite well in this regard: they spend months drafting and polishing lengthy opinions in argued cases, and they release their decisions to be consumed, interpreted and scrutinised by everybody. But this month, by keeping their reasoning close their robes on several big decisions, the justices are falling down on their duty to share what they are thinking.

Six justices allowing Texas to enforce a voter-identification law that a federal judge had characterised, in a 147-page decision, as a racist poll tax—and to do so with pursed lips—is not merely rude. It is a breach of the Court's legitimacy in a constitutional democracy. When the stakes are this high, all the justices should follow Justice Ginsburg's lead and stay up all night to explain to America just what they are up to and why.