Texas is set to carry out on Thursday the execution of a man whom experts for both prosecutors and defense attorneys have said is intellectually disabled, after an eleventh-hour Supreme Court ruling.

The U.S. Supreme Court overturned the stay on Edward Busby’s execution an hour before he was scheduled to receive a lethal injection, a week after the 5th U.S. Circuit Court of Appeals had issued a stay to further review his claims of intellectual disability.

The Texas attorney general’s office asked the U.S. Supreme Court to lift the stay, calling Busby’s claims of intellectual disability “meritless.” The office also argued that Busby’s claims should not be reviewed because they are “time barred” and previous similar appeals have been rejected.

Justices Elena Kagan, Ketanji Brown Jackson and Sonia Sotomayor all opposed the decision. Jackson, joined by Sotomayor, excoriated the order in an unusually brief dissent.

“Today, the Court finds itself unable to tolerate even a brief delay,” Jackson wrote. “In capital cases, we rarely intervene to preserve life. I cannot understand the Court’s rush to extinguish it, much less in the circumstances of this case.”

Busby’s lawyers filed another stay request with the 5th Circuit immediately following the Supreme Court’s decision, which was dismissed.

In 2002, the Supreme Court ruled against the execution of intellectually disabled people, but has given states some discretion to determine whether or not someone is intellectually disabled. Busby’s attorneys repeatedly argued he should be barred from being put to death because an expert called by the defense — as well as one hired by the Tarrant County District Attorney’s Office, which prosecuted the case — considered him to be intellectually disabled.

Busby was convicted and sentenced to death in November 2005 for the kidnapping and murder of Laura Lee Crane, a 77-year-old retired professor from Texas Christian University, a year earlier.

His execution had been halted twice before the 5th Circuit Court of Appeals’s decision last week — in 2020 because of the COVID-19 pandemic, and again in 2021 by the Texas Court of Criminal Appeals to review an intellectual disability claim.

If Busby receives a lethal injection as scheduled Thursday night, he would be the 600th person executed in Texas since the state’s 1982 decision to resume allowing the death penalty.