Eleven people are scheduled to be killed by the state in August (four in Texas, for whatever that's worth). It's the standard situation. People who lived horrible, horrible lives and had terrible things done to them turned around and perpetrated dreadful crimes. The condemned prisoners include the mentally ill and at least one mentally retarded person. You can read about each of the condemned prisoners here: NCADP. Only recently have we stopped executing juvenile offenders. Go here to read about the Supreme Court decision that changed our public policy. Among other things it admits that we had been in violation of several international treaties while it was our practice. We have executed people so mentally ill they couldn't understand that they were about to die. We have executed people whose attorneys slept through their trials.
So, it's not exactly a big intellectual leap to claim that we do this punishment thing badly. It's a certainty that we've had the wrong people on death row. It's almost certain that we've actually executed the wrong person; do a google search for Ruben Cantu if you want to know more. But if- through some miracle- we could execute perfectly, never getting it wrong, having it be more cost effective than life imprisonment, eliminating the racial bias, and only executing the competent.... would it then be all right?
It's hard to wrap my brain around that. Surely, the answer isn't killing better. The answer is being better. Being bigger. Having more integrity than the criminals who wreak such havoc in people's lives.