And this happens far more often than most people realize. In Canada alone, just under the letter "M," there were Donald Marshall, Jr., David Milgaard, Guy Paul Morin. Other famous reversals include Robert Baltovich, James Driskell, Anothony Hanemaayer, Ivan Henry, Rejean Hinse, Will Nepoose, Romeo Phillion, Thomas Sophoonow, Steven Truscott (I knew the author of the book "The Trial of Steven Truscott").
And the U.S. has a harsher justice system than Canada does, so how many do you suppose have been killed, or are rotting on death row, who were and are completely innocent? Since 1989, the United States has used DNA testing to exonerate 225 innocent people after they have spent years in captivity. At least 123 people have been exonerated from death row since the 1970s.
Just think if they had all been executed. What sort of compensation would the state have made in all our names to their families, once their innocence had been posthumously established?