It's so much more expensive to put people in jail. If they are in the custody of the state (jail or prison), they have to be given food, clothes, heating, and healthcare. Most of the people who are homeless have health problems--either problems that caused them to lose their homes, trauma from being on the street, substance abuse disorder, anything. The average person experiencing homelessness is much sicker than the average American.
At this point, the largest healthcare provider in the U.S. is the Department of Justice. And legally speaking, they have to provide care. (Granted, a lot of places will avoid that as much as possible, but ideally, they get what treatment they need.) There is a giant prison in Rochester, MN, because it's next to the Mayo Clinic. It's where people with rare and serious illnesses go. My old psych prof worked there part time, providing counseling. He saw people who committed horrendous crimes getting surgeries and chemo. To be clear, prisoners should be getting surgeries and chemo. They deserve healthcare. But it's jarring to hear that a murderer got a tumor taken off his lung while his victims' families have to pay out of pocket for therapy.
I also need to point out that if you're giving people housing, you're just giving them housing. Maybe you include heating, water, and electricity. You aren't giving them clothes (uniforms). You aren't paying guards. You aren't installing metal detectors and cameras. You are just giving them a place to live. That's obviously much, much cheaper than prison.
I am horrified that I have to resort to spelling this out, but yes, this is the only argument Republicans will listen to. Give them the cost-benefit analysis
