At issue is whether Art. 37.071 allows innocent persons to be executed.
As to that question, the answer has to be yes. We know that innocent people are convicted of criminal offenses - whether it be speeding, drunk driving, sexual assault or murder - even with the state having to prove the elements of the alleged offense beyond all reasonable doubt. The jury must then decide whether "there is a probability that the defendant would commit criminal acts of violence" that would constitute a "continuing threat to society" and whether the defendant either intended to kill the victim or anticipated that a life might be taken.
Unlike the unanimous verdict required to convict, only 10 jurors must agree on the answers to both of the questions above. In other words, do 10 out of 12 people think a person might commit more acts of violence? You factor this in with the disqualification of potential jurors who could not vote for the death penalty and you have a combustible chamber just waiting to order the needle.