That's interesting, but there's always this question of whether it just pulls up in time something that would have happened anyway.

There's a similar phenomenon in economics where if you have a sale, what you do is pull forward demand, but most of those purchases would have happened anyway.

My point is that studies like this are often cited to say that drug enforcement doesn't work, and that it's better to have things like "safe injection sites," but the problem is that these two hypotheticals weren't actually being compared.

IMO anyone interested in San Francisco's drug problem should read Michael Shellenberger's San Fran Sicko.