The court, without comment, declined to take up the lawsuit filed by four death row inmates. As is customary, it gave no reason. Justices Ruth Bader Ginsburg and Sonia Sotomayor indicated they would have accepted the case.
Although this removes a significant barrier to restarting federal executions, it does not mean they will automatically proceed as scheduled. The individual inmates facing execution could file additional challenges, which could affect whether and when these sentences are carried out.
The Justice Department said in response that executions would proceed unless a lower court blocks them on other grounds. But given the Supreme Court's move, the department expects that it would wind up with the same result, said Kerri Kupec, a spokeswoman.
An attorney for one of the inmates assailed the Justice Department for its push to execute the four men, linking the move to the ongoing protests nationwide against police violence and racial injustice.
"Even as people across the country are demanding that leaders rethink crime, punishment and justice, the government is barreling ahead with its plans to carry out the first federal executions in 17 years," Ruth Friedman, the attorney, said in a statement after the court's decision was released.
"Given the unfairness built into the federal death penalty system and the many unanswered questions about both the cases of the men scheduled to die and the government's new execution protocol, there must be appropriate court review before the government can proceed with any execution," said Friedman, who represents Daniel Lee, the first inmate facing execution.
Friedman wrote in an email that with "substantial litigation pending" in other courts, the decision Monday was disappointing but "there are important challenges yet to be ruled on."
The executions scheduled to begin in July are part of the Trump administration's push to resume carrying out federal death sentences, an effort that has been delayed by the courts and criticized by murder victims' relatives, former judges and current and former law enforcement officials.
Attorney General William Barr announced last summer that the department planned to resume executions using a new lethal-injection procedure that involves a single drug, pentobarbital.
After the original timetable was scuttled by challenges to the new lethal injection procedure, the Justice Department announced plans to carry out three executions in July and a fourth in August. All involve inmates convicted of murdering children.
A district judge said last year that the government's new protocol was inconsistent with the Federal Death Penalty Act, a 1994 law requiring that federal executions be carried out "in the manner prescribed by the law of the state in which the sentence is imposed."
The Justice Department had unsuccessfully appealed to the Supreme Court to let it begin carrying out executions last December, but the high court declined, letting the case play out before a lower court. A panel of the U.S. Court of Appeals for the D.C. Circuit ruled 2 to 1 this spring that the executions could move forward.
Two judges - Gregory Katsas and Neomi Rao, both recent nominees of President Donald Trump - lifted the district judge's injunction. But the two disagreed on the legal reasoning.
Katsas concluded that the law applies only to the top-line choice among execution methods, such as whether to use lethal injection instead of hanging or electrocution.
Rao, meanwhile, found that the law also requires the federal government to follow execution procedures set forth in state law, but not procedures set forth in less formal state execution protocols.
Judge David Tatel, nominated by President Bill Clinton, dissented. He wrote that for decades almost all federal executions were carried out by state officials who executed federal prisoners in the same "manner" as they executed their own.
Congress subsequently "signaled its intent to continue the same system - for federal executions to be carried out in the same manner as state executions," Tatel wrote.
Washington lawyer Catherine Stetson, representing the four inmates, said in a brief to the Supreme Court that such a splintered decision deserved the justices' attention.
"In permitting the government to proceed, the panel majority flouted [Supreme Court] precedent and upended key principles of administrative law rooted in the separation of powers," Stetson wrote, adding that the lower court's decision "raises more questions than it resolves about how to conduct federal executions."
Solicitor General Noel Francisco said that the lawsuit against the resumption of federal executions was simply a delay tactic, and that there was no argument that the proposed federal protocol was unsafe.
He said the court should resist the request to review the lower court when "the ultimate outcome of the case is clear."