> And unless they’re a danger to themselves or others (and
> not just in the sense of making bad life decisions), they
> can’t be held against their will.
Technically if somebody suffers from a mental illness, including addiction, they
could be forced off the street. In fact, refusing housing and other assistance to live in patently unsanitary conditions
could,
per se, be construed as evidence of incapacity.
We just choose not to. AFAIU, the Supreme Court decisions in the 1970s that, arguably, precipitated the dismantling of the archaic mental health institutions never even came close to suggesting that such people couldn't be forced off the street. For example, in the famous case of O'Connor v. Donaldson the patient, Donaldson, had actually been living in an apartment of his own in Philadelphia. He traveled to Florida to visit his parents, and it was his parents who had him committed after he shared paranoid delusions about his neighbors in Philadelphia. I've seen people use that case to argue against forcing people off the streets as-if we had no legal choice, but it's just plain wrong. Donaldson wasn't living on the streets; his ramblings notwithstanding he was clearly capable of taking care of himself, and in any event the case was never about his initial confinement but his continued confinement 15 years later.
We choose to let people live on the streets because we've somehow internalized the perverse logic that to do otherwise would result in a tyrannic state oppressing the mentally ill. (Myths about SCOTUS opinions come into being to bolster the logic.) That such an approach happens to require little or no budget outlays while simultaneously absolving us from moral blame is, I'm sure, merely coincidental....