We have far too many people serving lengthy stints in prison. There are also many who have no hope of getting out.
Those within the prison walls, need to be able to opt in for lethal injection.
If a convict completes three counselling sessions with a licensed mental health professional to become eligible. The professional is not really there to determine sanity, but to ensure that the convict is making this choice of their own free will and is mentally fit to make such a decision.
This would allow them to stop being a burden on their families, society, and themselves. This would leave more funding available for those that want it and where it may be more beneficial.