I think this argument only makes sense if you already oppose capital punishment in the first place (which I do, for the record). Like yes, if it turns out that we could have radically extended the lives of death row inmates and failed to do that, then that would be very bad for the inmates. But the entire point of executing someone is that being executed is very bad for you.
(The rehabilitation and isolation arguments already give no reason to prefer execution over prison.)
This is reasonable I think. Two thoughts:
First, pausing executions matters more now (if there is a meaningful chance of radical life extension or longevity escape velocity) than a pause would without the possibility, because it could save 200 or infinite or whatever years of human life vs say 40 years for a 35 year old. You’re right that this is geared towards those already opposed to capital punishment, but I think that’s ok. It just raises the stakes of every death in the interim.
Second, ASI itself might lead to less retributive thinking, especially if one believes that retribution stems from an improper understanding of free will and blameworthiness, and thinks that improved cognition through ASI enabled cognitive enhancement will allow people to understand more clearly. I am not certain this is true, but if I had to bet, would bet >50% that a smarter population after ASI would be less retributive.
rehabilitation
Through mind alteration? Some people might prefer to die. I understand that you might want to keep them alive to make the choice, but can we be sure to take forced mind alteration off the table?
Perhaps ASI will allow more people to see the futility of retribution.
I don't see how that happens unless it forcibly alters their minds. Why would people change at a deep level like that?
We have people who at least claim to believe that the Holy Spirit can rehabilitate people... and still want the death penalty, including for prison converts, for retributive reasons.
We have people who like retribution so much that they'll accept Kant's bizarre rationalizations for it.
We have people who literally don't seem to see any difference between "justice" and "retribution" as concepts.
Some people just seem to really like retribution. I don't know why; I personally think it's stupid. But I don't think my view has anything to do with determinism, and I doubt their view has anything to do with a lack of it.
"Through mind alteration?" Yes. I think there are already (very) early signs of mind alteration in terms of GLP1s effect on addiction, I would expect more things along those lines.
"Some people just seem to really like retribution. I don't know why; I personally think it's stupid. But I don't think my view has anything to do with determinism, and I doubt their view has anything to do with a lack of it." Hmmmm, I disagree here but am open to being convinced. Most people's moral intuition for retribution seems to stem from the idea that a criminal chose to break the law, and so deserves punishment. A proper understanding of causation and determinism would seem to negate the idea that criminals have meaningfully chosen in any sense worthy of punishment.
If one takes AGI/ASI timelines seriously, it seems possible that many people alive today on death row, if they manage to avoid being executed, could reap the benefits from life extension (or more sci-fi alternatives) in addition to perfect rehabilitation. Aligned ASI seems to solve most/all traditional justifications for punishment: rehabilitation (no poverty, no fetal alcohol syndrome, pharmacological cures for violent propensity, low IQ, poor impulse control etc.), isolation probably isn't necessary with enhanced monitoring/surveillance (itself somewhat dystopian). That leaves retribution, which is not solved, but never made such sense anyways to physical determinists and free will skeptics. Perhaps ASI will allow more people to see the futility of retribution.
One problem is that all of this sounds nuts, and policy makers might not (yet) take any of it seriously, and prisoners are a low-leverage group. But prominent policy makers are increasingly taking account of things that sound crazy.
I am an appellate criminal defense lawyer in the South, and it seems quite likely that we will all be ashamed in 10-20 years that we allowed executions to continue.