ST. LOUIS -- A federal judge in Missouri has ruled that the state's method of executing condemned prisoners by injection is constitutional.

The ruling by U.S. District Judge Fernando Gaitan in Kansas City late Tuesday presumably opens the door for executions to resume after nearly three years.

Last July, a group of Missouri's condemned prisoners filed suit in federal court, claiming the state's history of using unfit and untrained personnel as executioners could expose them to unconstitutional pain.

But Gaitan, who two years ago issued a moratorium on executions in Missouri over similar concerns, now says the state's revised procedures are constitutional.

On Friday, the Missouri Supreme Court postponed the execution of John Middleton, scheduled for July 30, allowing the federal court to sort things out. There was no immediate word on rescheduling it.

The Department of Corrections said Wednesday if the execution stay is lifted, it would carry out the execution. Ginger Anders, one of the attorneys representing inmates in the suit, said only, "We're considering our options."

Gaitan wrote Tuesday that the Department of Corrections' revised procedures, which he ordered in 2006, leaves "very little discretion" to individual execution team members. And, he said the team itself, which Corrections contends now includes an anesthesiologist and nurse, "are fully qualified to carry out the steps."

The condemned inmates' attorneys deposed Corrections director Larry Crawford and wanted to ask team members how they planned to carry out their assigned duties.

But Gaitan wrote the law doesn't allow them to select the most qualified medical people to serve on the execution team. Nor does it provide for their "input into who will be performing the executions, as long as they have the requisite experience and are licensed in their field."

Corrections, which had told the court it was having difficulty finding a doctor to assist in executions, said last month its execution team was finally in place.

In court papers, Corrections said its team includes a nurse and an anesthesiologist, despite professional guidelines against doctors taking part in executions.

The team's duties include preparing the chemicals, inserting intravenous lines, monitoring the prisoner and supervising the injection of chemicals by Corrections employees, all of which violate professional medical groups' policies against physician participation in executions.

In 2006, the surgeon who previously oversaw the state's executions, Dr. Alan Doerhoff, testified in another court case that he was dyslexic, sometimes transposed numbers, and operated without written procedures or supervision. That disclosure prompted Gaitan to require Missouri to adopt a written protocol, drop Doerhoff from the team and impose an execution moratorium that was later lifted.

In the last year, Attorney General Jay Nixon has asked for execution dates for 14 of the roughly four dozen prisoners awaiting the death penalty.

Missouri hasn't executed an inmate since convicted killer Marlin Gray was put to death in October 2005. The next in line, convicted killer Michael Taylor, won an 11th-hour stay of execution in February 2006.

Taylor's subsequent challenges to Missouri's lethal injection procedures prompted Gaitan's 2006 moratorium.

Missouri wasn't alone. A number of states that use lethal injection withheld executions while the U.S. Supreme Court considered the constitutionality of the procedure.

The Supreme Court in April upheld it, but left the door open to challenging lethal injection procedures in states where problems with administering the drugs are well documented.