Did Joseph Wood suffer when he was executed in Arizona this summer? 

Some witnesses reported that Wood gasped over 600 times during his July 23 execution by lethal injection, which took nearly two hours. But one official said that Wood "appeared to be snoring," while another stated flatly that the inmate "did not endure pain." We'll never know. 

But here's what we do know: The quest for a pain-free mechanism of capital punishment is a fool's errand. As Amherst professor Austin Sarat shows in a terrific new book, "When the State Kills," we have spent two centuries trying to put people to death without putting them in discomfort. And it hasn't worked. 

Start with hanging, which Englishmen brought to our shores during the colonial era. But they did not import professional hangmen, so executions fell to sheriffs and other local officials. 

Too often, they had no idea what they were doing. Poorly tied ropes snapped, earning the condemned a return trip to the gallows. Or sometimes the rope wasn't taut enough, so executioners had to pull on the prisoner's legs until he expired. 

So communities erected higher gallows, in the hopes that a so-called "long drop" would insure a quick and painless demise. They also devised pulley systems to jerk the prisoner's head upward, instead of relying on gravity alone. 

But many inmates still gurgled and choked for long stretches of time; others were decapitated, generating lurid newspaper headlines. 

So Americans turned to the new technology of electricity, which promised to execute prisoners "in a less barbarous manner," as New York's governor declared in 1885...