We've had many moratoriums. There was a nationwide moratorium on the death penalty back in (I think) the 70s because of a U.S. Supreme Court decision. Other states have at times temporarily halted the death penalty. But there are no reports of an innocent person being executed. I know some people have been on death row and later exonerated, but I don't think it's accurate to say we are executing innocent people.
The exonerations shows that innocent people have been on death row.
I respect anyone who believes that every person who was innocent has been "saved", exonerated.
I just believe it to be very unlikely, or rather, I don't believe it for a minute, but that's just me.
I base my beliefs on the fact that our justice system has flaws, and wrong sentencing are handed out every day, be it too long, too short or whatever.
-Hedge