Alabama’s attorney general on Monday asked the U.S. Supreme Court to let an execution proceed this week, arguing that questions about a lethal injection drug have been settled by the courts.

Attorney General Steve Marshall’s office asked the justices to let the state proceed with Thursday’s scheduled execution of Robert Melson who was convicted of killing three Gadsden restaurant employees during a 1994 robbery.

The 11th U.S. Circuit Court of Appeals last week granted a stay as it considers appeals from Melson and other inmates who contend that a sedative used by Alabama called midazolam will not render them unconscious before other drugs stop their lungs and heart. The state argues there was no reason to grant the stay since midazolam’s use in lethal injections has been upheld by the high court, and the court has let executions proceed using midazolam in Alabama and Arkansas.

“Alabama has already carried out three executions using this protocol, including one less than two weeks ago in which this court, and the Eleventh Circuit, denied a stay,” lawyers with the attorney general’s office wrote in the motion

“If the stay is allowed to stand, Melson’s execution will be delayed many months, if not years. The State, the victims’ families, and the surviving victim in this case have waited long enough for justice to be delivered. This Court should vacate the lower court’s stay,” attorneys for the state wrote.

Melson is one of several inmates who filed lawsuits, which were consolidated, arguing that the state’s execution method is unconstitutional. A federal judge in March dismissed the lawsuits, and the inmates appealed to the 11th Circuit saying the judge dismissed their claims prematurely.

A three-judge panel of 11th Circuit judges did not indicate whether they thought the inmates would succeed in their appeals. Rather, the judges wrote Friday that they were staying Melson’s execution to avoid the “untenable” prejudging of the inmates’ cases.

Midazolam is supposed to prevent an inmate from feeling pain, but several executions in which inmates lurched or moved have raised questions about its use. An Arkansas inmate in April lurched about 20 times during a lethal injection. Melson’s lawyers wrote in a Friday motion that Alabama “botched” a December execution in which inmate Ronald Bert Smith coughed and moved for the first 13 minutes.

“Mr. Smith’s botched execution supports the argument that midazolam is a vastly different drug than pentobarbital. It does not anesthetize the condemned inmate, and because it does not anesthetize, defendants’ use of potassium chloride is unconstitutional,” Melson’s attorneys wrote last week.