As a member of the U.S. Court of Appeals for the 10th Circuit, Supreme Court Justice Neil M. Gorsuch rejected stay-of-execution requests, but he had limited exposure to the issue of capital punishment until Thursday’s vote. (Ricky Carioti /The Washington Post)

Supreme Court Justice Neil M. Gorsuch cast his first consequential vote Thursday night, siding with the court’s other four conservatives in denying a stay request from Arkansas death-row inmates facing execution.

Hours later, the state executed one of the men, the first lethal injection carried out there since 2005.

New justices have described being the final word on whether a death-row inmate is executed — often during a late-night, last-chance appeal to the Supreme Court — as a time when the responsibility of the role crystallizes. Indeed, one of the court’s most solid death-penalty supporters, Justice Samuel A. Alito Jr., was tasked on his first full day as a justice in 2006 with deciding whether to dissolve a stay that kept Missouri from going forward with an execution. The stay was upheld, and Alito was not listed among the dissenters.

[In first case, Alito upholds stay for Missouri inmate]

Gorsuch’s reasoning for his vote is not known. Neither he nor the other justices who turned down the request explained the decision. But Gorsuch was sworn in on April 10, and he has had some time to study Arkansas’ well-publicized attempt to execute several inmates before a drug used in their planned lethal injections expires.

The court’s four liberals — Justices Ruth Bader Ginsburg, Stephen G. Breyer, Sonia Sotomayor and Elena Kagan — said they would have stayed the executions.

Breyer wrote that the case supports his call, which Ginsburg has joined, for a review of whether the death penalty can be constitutionally applied.

[Gorsuch sworn in as 113th Supreme Court justice]

“Why these eight? Why now? The apparent reason has nothing to do with the heinousness of their crimes or with the presence (or absence) of mitigating behavior,” Breyer wrote. Instead, Breyer wrote, “apparently the reason the state decided to proceed with these eight executions is that the ‘use by’ date of the state’s execution drug is about to expire. In my view, that factor, when considered as a determining factor separating those who live from those who die, is close to random.”

As expected, Gorsuch’s decisions have been closely scrutinized. A new justice’s role on the court is only broadly sketched during confirmation hearings, and each decision begins to fill in the outlines of a lifetime appointment.

Gorsuch rejected stay-of-execution requests as a member of the U.S. Court of Appeals for the 10th Circuit, but he has had limited exposure to the issue of capital punishment.

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During his Senate confirmation hearings, he was often asked about a passage in a book he wrote, in which he criticizes euthanasia and doctor-assisted suicide. “All human beings are intrinsically valuable, and the intentional taking of human life by private persons is always wrong,” he wrote.

The phrase “by private persons” was key to Gorsuch’s response.

Some online commentators have questioned what Thursday night’s action says about Gorsuch’s antiabortion credentials. He has a thin record on which his view of a constitutional right to abortion could be assessed. But if he supports the constitutionality of the death penalty and questions a constitutional right to abortion, he would simply be reflecting the various positions on the court he is joining.

The justice he replaced, Antonin Scalia, felt the same on capital punishment and abortion. Liberals such as Breyer and Ginsburg are the opposite, supporting abortion rights while raising doubts about the death penalty.

Gorsuch has faced an immediate immersion at the Supreme Court. He was sworn in April 10. He skipped the justices’ private conference that week to prepare for oral arguments that began last Monday.

Although he asked no questions in one oral argument, he was an active participant in the other six. Some analyses showed that he asked more questions than many of his colleagues did in their first outings on the court, and he displayed a confidence born of his decade on the bench.

On Friday, he was scheduled to meet with the rest of the court to examine a long list of cases that would be on the docket that begins in October. When it had only eight members, the court seemed to shy away from some controversial topics.

But the new list is anything but neutral. It includes cases involving warrantless searches of cellphone records, voting rights and whether businesses can for religious reasons refuse their wedding services to same-sex couples.