Given the fact that Texas is known as the execution capital of the country, another execution anniversary would normally come as no surprise. But what sets Willingham's situation apart is that he was likely innocent of the crime for which he was sentenced to death.
Willingham had been convicted of an alleged arson that claimed the lives of his three daughters in 1991. However, a later forensic review of the case led to the conclusion that "a finding of arson could not be sustained." In other words, the fire for which Willingham was executed was probably just an accident. David Grann wrote an excellent in-depth article about the case for the New Yorker, which can be found online here.
Willingham's case is not the only one in which an innocent person was likely put to death. There is evidence of at least a few more.
In addition, according to the Amnesty International, "over 130 people have been released from death rows throughout the country due to evidence of their wrongful convictions. In 2003 alone, 10 wrongfully convicted defendants were released from death row."
I cannot think of a better argument against the use of capital punishment. Death is permanent, and you cannot resurrect an executed individual if you later discover that you killed the wrong person. Would you want to be the juror or the executioner who made it happen?
Given the fallibility of the criminal justice system, the continued use of the death penalty is reckless and irresponsible. We as a nation should be above this kind of thing.