Matthew Yglesias links to a study and supporting info showing that it's cheaper by a factor of three to give homeless people homes than to let them languish in the streets and use up resources in emergency rooms and sending police to clear out public places. And the great part about that is that you don't need to create new spending to fix this problem; it would literally reduce costs in recognizable ways.

My first thought when seeing such spectacular results was that they might be due to the unique factor of the 2008 economic collapse, that because of that you had lots of capable people living on the streets who, if given a chance and a boost, could recover. And that outside of the (ongoing) 2008 crisis, you might not see such good results because then you're dealing solely with mentally ill people who just can't make it on their own. But that's actually not the case; the study includes assigning a case manager that ensures that people take their medication and make doctors visits and the like.

And credit where credit is due: this trial program was started under the Bush administration.