post-apocalyptic adaptations: monastery prisons

In an economy of declining or totally imploded cash flows, prisons are underfunded or totally inoperable, what do we do with violent criminals?

The Axis Powers of WWII give us the cautionary tale of simply eliminating undesirables. While I personally would like to see a lot of violent criminals eliminated, mine is just a particular framework of ethics and sense of priorities, and the civic space is one that shouldn't just pander to my framework. I can say that about everyone else's framework also. In a place like the U.S., we have a patchwork of mismatched societies all with different fews to the worth of a violent criminal's life.

The only objective thing we can say is the criminal committed the act, after which we plunge into each schism's hatred, care, or even veneration of the criminal.

Then lets use this divisiveness.

Those who have some sort of care or love of the criminal provide sanctuary, for life. The contract with the larger society is the criminal never exits the sanctuary again. If there is ever a problem, there is an abrupt eviction and execution, or if the monastery prison is found extremely negligent of responsible for the "problem", then monastery receives some sort of harsh Killdozer-esque response from the wider society.

This Monastery Prison model provides for varying degrees of tolerance and care, but does not subject the general civic polity to the burdens of the most tolerant sect's worldview.