One of three men convicted in the 1998 murder of James Byrd Jr, one of modern America’s worst hate crimes, is to be executed in Texas.
Byrd, a black man, was beaten, chained to a truck and dragged for miles by King, an avowed white supremacist, and two other white men.
His murder prompted Congress to pass hate crime legislation in 2009.
John William King, 44, is the second man to be executed over the slaying. He has filed multiple appeals in his case.
On Monday, the Texas Board of Pardons and Parole voted unanimously to deny King a commutation or a 120-day reprieve.
Last October, the US Supreme Court declined to take up his appeal, and so, barring a last-minute stay, King will be executed on Wednesday evening, at 18:00 local time (23:00 GMT).
King, a known racist with a criminal record, was the first white man to receive a death sentence for killing a black man in modern Texas history, according to the New York Times.
Prosecutors depicted him as the ringleader of the group of men who attacked Byrd.
Lawrence Russell Brewer, the other white supremacist who took part in Byrd’s killing, was executed in 2011, but King had been sentenced earlier.
The third man involved, Shawn Allen Berry, was spared the death sentence and is serving a life sentence instead as he did not share the white supremacist beliefs of Brewer and King.
He will be up for parole in 2038, US media report.
In the early hours of 7 June 1998, in Jasper, Texas, Byrd, 49, encountered Brewer, King and Berry on the way home from a party.
The three men assaulted Byrd, then chained him by his ankles to the back of a pickup truck and dragged him for several miles until he was dismembered.
Police found parts of Byrd’s body in front of a black church just outside the city; the rest was located over a mile away.
Authorities later followed a blood trail of evidence – including a lighter engraved with “KKK” and King’s nickname, Possum – placing the three men at the scene of the crime.
During King’s trial, prosecutors showed evidence detailing his hatred of black people, including a letter he attempted to send Brewer in jail glorifying their murder, the Washington Post reported.
“Regardless of the outcome of this, we have made history and shall die proudly remembered if need be… Much Aryan love, respect, and honor, my brother in arms.”
He had spoken of starting a race war and of initiating members of a white supremacist gang he belonged to by having them kidnap and murder black people, court documents showed.
King was convicted by a jury that deliberated just over two hours.
The case sparked nationwide horror and outrage, and in 2001, Texas passed the James Byrd Jr Hate Crimes Act to toughen punishments for such crimes.
Congress followed, enacting the Matthew Shepard and James Byrd Jr Hate Crimes Prevention Act of 2009 to strengthen laws against crimes committed over a person’s race, colour, religion, sexual orientation, gender, disability or national origin.
King has repeatedly and unsuccessfully tried to appeal his case at the state and federal level. He has maintained he is innocent, blaming Berry alone for the murder, and arguing that his lawyers did not properly defend him.
Jasper’s former sheriff, Billy Rowles, told the Post that King’s execution would finally provide closure for the community.
“It’s been a long wait and now it’s here, and I believe everybody will feel that this is the closure they needed.”