Nine states have now suspended executions over concerns about the potential cruelty of lethal injection, the method used by 37 of the 38 states that uphold the death penalty.
Last week a legislative commission in New Jersey recommended that the state abolish the death penalty altogether.
And juries have become more reluctant than ever to impose the ultimate punishment: U.S. death sentences fell to 114 in 2006, according to an estimate from the Death Penalty Information Center, reaching their lowest level since the country reinstated the death penalty 30 years ago.
"Publicity surrounding wrongful convictions is the driving force behind that decrease," says Richard Dieter, the center's executive director. "The government has not been doing a good job with the death penalty, and the public seems to be pulling back."
Executions have declined too -- 53 last year, the lowest number in a decade. And that trend is likely to accelerate for one big reason: new challenges to lethal injection as "cruel and unusual" punishment.
Under this method, an anesthetic is injected first to render the prisoner unconscious, a second drug paralyzes the prisoner and a third stops the heart. But when the procedure is not administered properly, it can be excruciating. If, for instance, the prisoner is not anesthetized sufficiently, he or she would feel searing pain when the third injection is given but could not indicate that because of the paralyzing second drug.
Florida suspended the death penalty last month after the botched execution of convicted murderer Angelo Diaz. It took 34 minutes and two doses of lethal chemicals for Diaz to die because officials improperly inserted the needles into his arms.
On the same day that Florida stopped executions, a California judge said the lethal injection protocol violated the Eighth Amendment ban on cruel and unusual punishment and was therefore unconstitutional.
Now all eyes are on Missouri, where the challenge to lethal injection reached a federal appeals court Wednesday. A lower court halted executions last summer after the doctor who supervised Missouri's lethal injections admitted he was dyslexic and sometimes "improvised" the deadly mix of drugs. Lawyers trying to stay the execution of convicted murderer Michael Taylor received those startling admissions when they deposed the doctor, identified in court papers as John Doe 1.
One of those attorneys, Ginger Anders, says they discovered that "Missouri never had a written protocol. John Doe just did what he wanted to do on the night of the execution."
The lower court ordered that executions in Missouri could not resume until the state found a board-certified anesthesiologist to oversee them. Try as it might, however, the department of corrections could not find one doctor in the state to work the death chamber.
Brian Hauswirth, a spokesman for Missouri's Department of corrections, says the state now has a written protocol for lethal injection that is "humane and constitutional," and it should be allowed to resume executions. But when asked if a doctor helped to prepare the new procedure, Hauswirth says he was "not aware of any doctors involved in documenting the protocol."
It may be months before the appeals court decides if Missouri's lethal injection protocol is constitutional. But as this case has now reached the highest judicial level, just shy of the Supreme Court, most observers say other states confronting challenges to lethal injection will be watching closely and waiting before they use this method again.
Dieter says all these developments indicate that while "the country is not about to get rid of the death penalty, the tide has turned to a certain extent."