UPDATE 5-U.S. completes 2nd execution in a week, dividing judges and victims' families

(Writes through with comments from family of Purkey's victim, Supreme Court justice's dissent, other details)

By Jonathan Allen

July 16 (Reuters) - The U.S. government executed a convicted murderer on Thursday in the second federal execution in as many days after a 17-year pause, overcoming court orders that said condemned men should have time to contest the legality of a new one-drug lethal-injection protocol.

Following another overnight of volley of final legal challenges that were cleared away in the small hours by the Supreme Court, Wesley Purkey was pronounced dead at 8:19 a.m. EDT (1219 GMT) at the federal prison in Terre Haute, Indiana, the U.S. Bureau of Prisons said.

The resumption of capital punishment this week has divided the public, the families of the condemned men, Supreme Court justices and others.

Relatives of the victims of Daniel Lee, who was executed on Tuesday, opposed his execution in anguish, noting his accomplice in the murder of an Arkansas family in 1996 had been sentenced instead to life in prison.

In contrast, the family of Jennifer Long, the 16-year-old girl raped and murdered by Purkey in Missouri 1994, expressed relief on Thursday morning after witnessing Purkey's death.

"We took care of today what we needed to take care of," William Long, the girl's father, told reporters. "It has been a long time coming. He needed to take his last breath, he took my daughter's last breath. And there's some resolve."

If a third convicted murderer is put to death on Friday as planned, President Donald Trump's administration will have completed as many federal executions in a single week as happened in the preceding 57 years, though executions by some state governments remain common.

The Justice Department began efforts to revive capital punishment in the federal justice system soon after Trump's inauguration in 2017, announcing last year it would replace the old three-drug protocol with lethal injections of a single drug: pentobarbital.

The department sought to end a de facto moratorium engendered by a spate of botched executions, legal challenges and difficulty in obtaining lethal-injection drugs. It spent much of 2018 and 2019 building a secret network of companies to make and test the drug, some of which were identified in a Reuters investigation last week.

Inmates on federal death row, including Purkey and Lee, sued the Justice Department over the protocol, saying it would cause unconstitutional suffering as the caustic drug quickly filled their lungs with bloody fluid before they lost consciousness.

U.S. District Court Judge Tanya Chutkan in Washington is overseeing the lawsuits, which are ongoing even as the plaintiffs are put to death by the defendants one by one.

She sided with some of the condemned men's arguments, issuing injunctions once last year and twice this week in order to let their lawsuits play out, which were each overturned by higher courts.

Twice this week, a 5-4 majority in the Supreme Court cast out Chutkan's injunctions. But the court's liberal justices have questioned whether any form of capital punishment can be allowed.

Justice Stephen Breyer wrote in a dissenting opinion this week that "the resumption of federal executions promises to provide examples that illustrate the difficulties of administering the death penalty consistent with the Constitution."

Lawyers for Purkey, 68, had argued that his Alzheimer's disease had advanced to the point that he longer understood why he was being executed, but he was lucid in his final words while strapped to a gurney.

He apologized to his victim's family and to his own daughter for the "pain and suffering" he had caused them, according to a reporter who was allowed to witness the execution and share notes with other outlets.

"This sanitized murder really does not serve no purpose whatsoever," Purkey said a few minutes before he would be pronounced dead. "Thank you." (Reporting by Peter Szekely and Jonathan Allen in New York; Writing by Daniel Trotta; editing by Jonathan Oatis and Bernadette Baum)