Timothy Johnston, who tried to hold off his execution by...

Timothy Johnston, who tried to hold off his execution by arguing that Missouri's system of lethal injection is unconstitutionally painful was put to death early today for beating his wife to death in 1989.
Johnston, 44, was pronounced dead at 12:07 a.m. in the death chamber at the Bonne Terre prison, 60 miles south of St. Louis.
Lawyers for Johnston had argued vigorously in federal courts that Missouri's three-drug method of execution presented the threat of a "painful and protracted death," in violation of the U.S. Constitution's bar to cruel and unusual punishment.
Johnston confessed murdering his wife, Nancy Johnston, 27, by beating and kicking her on June 30, 1989.
Johnston's constitutional claim was rejected Friday by a U.S. District Court judge downtown, but he won relief Tuesday from a 3-judge panel of the Eighth U.S. Circuit Court of Appeals in St. Louis. The 2-1 vote put an eight-day stay on the execution.
Missouri Attorney General Jay Nixon then appealed to the full bench of the Eighth Circuit, which overruled the stay shortly before 9 p.m. Johnston's lawyers then appealed to the U.S. Supreme Court, but their plea was rejected.
Also Tuesday evening, Gov. Matt Blunt declined to use his power to reduce Johnston's sentence to life in prison.
Johnston's claim against lethal injection was one of several have been raised across the country against the practice. Trial-level judges generally have rejected the claim, but appeals are pending in three states.
Missouri is one of 27 states that carry out executions by administering a series of three drugs intravenously in rapid succession. The procedure begins with a heavy sedative to render the condemned unconscious, followed by a drug to end breathing and another to stop the heart. The sedative, sodium pentothal, renders the condemned motionless within seconds. Death usually is pronounced within four minutes.
Johnston's argument was that, if the state doesn't properly administer the sedative, he could be conscious during the other drugs and experience "a painful and protracted death."
After a hearing Friday, U.S. District Judge Charles A. Shaw rejected Johnston's claim as speculation, adding, "The ever-present possibility of human error or accident is insufficient to establish a constitutional violation."
Johnston becomes the 4th condemned inmate to be put to death this year in Missouri, and the 37th in the USA.