In Texas, death sentences hinge on a concept called “future dangerousness”; that is, the jury has to determine whether or not the defendant will commit violent crimes in the future. If they decide he will, then, and only then, can they sentence him to death. Clearly, once off drugs, David Lee Powell has not been a danger to anyone and no longer qualifies for execution.
The problem with the death penalty (well, one of the problems) is that it doesn’t allow for the fact that people can change and improve. In fact, it cancels out the very possibility of human redemption. Capital punishment is based on a depressing philosophy that bad people (or people who do bad things) will always be bad. Certainly, human beings are capable of doing terrible things, but they are also capable of doing remarkable good, or at least doing better, if we don’t execute them first.
One of the purposes of executive clemency is to consider factors like this (remorse, redemption) that are out of the purview of the courts. The Texas Board of Pardons and Paroles has a chance to recommend clemency in David Powell’s case, and assert on behalf of the people of Texas that, yes, sometimes people can change.