The Trump administration announced plans Thursday to resume executing federal prisoners awaiting the death penalty — ending a 16-year moratorium on the practice and setting the stage for fresh legal challenges.

Attorney General William P. Barr ordered the Bureau of Prisons to schedule executions for five inmates on death row. Each was convicted of murdering children, among others.

“The Justice Department upholds the rule of law — and we owe it to the victims and their families to carry forward the sentence imposed by our justice system,” Barr said in a statement.

By diving into the death penalty debate, the Trump administration is pushing back against the country’s recent trend of declining executions and putting the federal government squarely on the side of states trying to carry out death sentences.

A host of Democratic presidential candidates denounced the Justice Department decision and affirmed their opposition to the death penalty. In recent weeks, the Democratic field has sparred internally over criminal-justice issues, but the death penalty is a topic on which many of them are in sync.

Sen. Kamala D. Harris (D-Calif.), a former state attorney general, tweeted that capital punishment is “immoral and deeply flawed. Too many innocent people have been put to death. We need a national moratorium on the death penalty, not a resurrection.”

Groups opposed to capital punishment promised to fight the decision, arguing that federal death penalty cases are infected with many of the same problems as state executions.

Most states have the death penalty. Few actually carry out executions.

The last federal execution was in 2003. In the years since, there has been an informal stoppage as Justice Department officials reviewed its lethal-injection procedures. That practice was underscored during the Obama administration by then-Attorney General Eric H. Holder Jr.’s personal opposition to the death penalty, even while he approved prosecutors’ decisions to seek the death penalty in specific trials.

Barr ordered the Bureau of Prisons to adopt a new policy for lethal injections, one that officials said closely mirrors the protocols used in Georgia, Missouri and Texas, replacing a three-drug lethal combination with one drug, pentobarbital.

The Justice Department has scheduled executions in December and January for the following prisoners: Daniel Lewis Lee, for the killing of a family of three, including an 8-year-old girl; Lezmond Mitchell, for the killing of a 63-year-old and her 9-year-old granddaughter; Wesley Ira Purkey, for the rape and murder of a 16-year-old girl and the murder of an 80-year-old woman; Alfred Bourgeois, for molesting and killing his 2-year-old daughter; and Dustin Lee Honken, for shooting and killing five people, including two children.

Cassandra Stubbs, head of the American Civil Liberties Union’s Capital Punishment Project, said the group would challenge the Justice Department decision.

“Under no circumstances should the Justice Department be allowed to rush through executions. The federal death penalty is defined by the same problems of racial bias, geographic disparities, prosecutorial misconduct and junk science that have led to the decline in support for capital punishment nationwide,” Stubbs said. “The DOJ is on the wrong side of history again.”

Attorney Morris Moon, who represents Lee, the first inmate scheduled to be executed, said he was troubled by the government’s actions Thursday.

“We had no advance notice whatsoever,” Moon said in an interview. “We found out about the protocol at the same time the public did, about the same time we found out from the prison that our client had an execution date set.”

Moon did not say whether Lee’s attorneys would challenge the new protocol in court, saying: “We’re considering all of our options.” He said there were problems with “the fairness and reliability” of his client’s death sentence.

Nationwide decline

The executions scheduled Thursday all involve people convicted between 1999 and 2004, according to the Justice Department. For some relatives of victims, the long gap between death sentences being handed down and then carried out can linger in their lives.

Genie Boren said waiting essentially made her feel “on hold.” Her husband, Cecil Boren, was killed in 1999 by Kenneth Williams, who was sentenced to death and then executed by Arkansas in 2017. But after seeing Williams’s execution, she said, that feeling is gone.

“I don’t have to sit and wonder when it’s going to happen, or if it’s going to happen,” she said. When she saw the sentence carried out, Boren said, she felt relief “that it was finally over and done with.”

Boren said she worries that innocent people will be executed, pointing to stories of people exonerated and freed from death row. But in cases where they know for sure — “in our case, we knew,” she says — Boren supports the death penalty and the Justice Department’s announcement.

“The jury made that decision that they should get the death penalty,” she said. “And I think a person that does wrong like that, they have to pay some penalty for that.”

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The number of executions nationwide has plummeted over the past two decades, falling to 25 last year, down from 98 in 1999. The number of states carrying out death sentences has also declined as some have abolished capital punishment, announced moratoriums or struggled to obtain the drugs sought for executions.

New Hampshire abolished the death penalty this year, making it the 21st state to formally abandon capital punishment. In some of the other states where it remains the law, the death penalty is effectively frozen, including by governor-issued moratoriums in California and Pennsylvania and a court order in North Carolina.

Supporters of capital punishment, who argue that it should be applied for heinous crimes, have said that delays in carrying out death sentences are unfair to the relatives of victims. Opponents of the practice have argued the system is dangerously flawed, pointing to cases of people who have been exonerated after being sentenced to death.

Ruth E. Friedman, head of the Federal Capital Habeas Project, which seeks to improve legal representation for people on federal death row, said there were “troubling questions about the new execution protocol.”

“A pervasive myth is that the federal death penalty is ‘the gold standard’ of capital punishment systems, applied only to the worst offenders for a narrow class of especially heinous crimes involving unique federal interests, with highly skilled and well-resourced lawyers on both sides,” she said in a statement. “This is false.”

Friedman called for “additional court review before the federal government can proceed with any execution.”

States are scrambling to keep using lethal injections

Nationwide, a majority of Americans support the practice, though that number has declined significantly since the mid-1990s. At that time, when crime rates were far higher, 4 in 5 Americans backed capital punishment, while a Pew Research Center poll last year found that 54 percent of people supported it.

According to Pew, most Republicans still back it, while Democrats oppose the death penalty. President Trump has been an outspoken supporter of capital punishment for decades.

New protocol

The Justice Department’s decision to shift to a single drug for lethal injections — which remain the primary method of executions nationwide — mirrors a move that has taken place in states where officials have faced difficulties in obtaining the drugs.

States still seeking to schedule executions have scrambled to obtain lethal-injection drugs in recent years in the face of opposition from pharmaceutical firms that do not want their products used in carrying out death sentences.

Companies have tightened their restrictions on how such drugs are sold, and in some cases have gone to court to try to prevent them from being employed to carry out death sentences.

In some states, authorities have moved to rewrite their execution protocols to rely on different drug combinations — in some cases, doing so multiple times — or expanded their ability to use other execution methods such as firing squad, electric chair and nitrogen gas. Nebraska last year became the first state to use the powerful opioid fentanyl in an execution.

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Texas, Georgia and Missouri — three of the 11 states that have carried out executions since 2017 and all among the country’s most active death penalty states — have shifted their protocols from three-drug combinations to relying only on pentobarbital, according to the Death Penalty Information Center.

It’s unclear whether the Justice Department’s shift to pentobarbital will encourage other states to do the same.

The Justice Department has sought and won death sentences in two high-profile cases in recent years, sending both the Boston Marathon bomber and the Charleston, S.C., church gunman to death row.

When Dzhokhar Tsarnaev, the surviving Boston Marathon bomber, was sentenced to death in 2015, the Justice Department was operating under a de facto moratorium on executions due to an ongoing review of federal death penalty policy. The government lacked the drugs needed to carry out an execution at that time.

It was not immediately clear whether the federal government had obtained the pentobarbital needed for the executions announced Thursday. The Bureau of Prisons declined to comment.

Toward the end of the Obama administration, the bureau said it was still “in the process of revising its execution protocol.” Earlier this year, the Bureau of Prisons declined to address whether the agency was attempting to obtain the drugs used for executions.

An addendum describing the updated protocol was submitted Thursday by federal officials as part of a lawsuit filed more than a decade ago by death-row inmates challenging the previous three-drug procedure.

The addendum is similar in many ways to a previous protocol — dated Aug. 1, 2008 — that a Justice Department official had said in 2015 was the procedure being reviewed under President Barack Obama.

But it has some notable differences. The 2008 protocol had language the new document lacks, including guidance for what to do if “a situation not contemplated in this procedure” occurs, which could lead authorities to pause the execution, close the curtains to witnesses or escort them out.

The older protocol also said officials, including medical personnel, may conduct “a complete assessment” and then determine if the execution should resume, start from the beginning or be rescheduled. That language does not appear in the new document.

A Justice Department spokesman declined to comment on the differences between the two protocols.

Federal death sentences account for a fraction of the more than 2,600 people on death row in the United States. Executions are also extremely rare for federal prisoners, with the government carrying out three executions since the federal death penalty statute was expanded in 1994.

In 2001, the government executed Timothy McVeigh for the Oklahoma City bombing and Juan Raul Garza for murdering three men. The last federal inmate to be executed was when Louis Jones Jr. was put to death in 2003 for the kidnapping, rape and murder of 19-year-old Army Pvt. Tracie Joy McBride. All three executions were carried out using the three-drug protocol.