Cain and Able.
Oh; it WOULD be nice to use a video image of the inside of someones head to make SURE that they didn't kill an innocent person AGAIN; but, would we not save MORE if we could STOP them before the act the FIRST time?
I wonder what the statistics say about RELEASED murderers.
Do THEY kill more; percentage-wise, than the general population?
Dunno.
But IIRC, Cornelia Wallace, wife of George, had Alabama prisoners as part of the household staff at the governor's residence in Montgomery.
She said she much preferred the convicted murderers to the other felons. They apparently weren't as conniving as the embezzles, muggers, thieves and other common criminals.
Oh, yes, of course.
The key word in your question is "if" and "if" is the biggest and most dangerous little word in the English language.
"If" we had the ability to reliably predict who would become a murderer, we could do that. But (another dangerous word!) BUT, until such a time as we can demonstrate that we actually do have that ability, the cost to an otherwise free society of some over-arching all-powerful self-absorbed and self-interested government deciding whither the threat and having the ability to lock up any uppity citizen because they might some day commit a crime is simply too high.
We can survive a few thousands or even tens of thousands random murders. (Current rate: about 15,000/year)
We cannot survive the systematic rounding up of tens of millions or even millions of potential troublemakers.
Do you seriously want this or any other administration to have that power?
Keep in mind that Bill Ayers, just a guy in Obama's neighborhood, just a guy he barely knew, in whose living room Obama launched his political career, openly advocated murdering 25,000,000 Americans, simply because it would be easier than attempting to "re-educate" them.