Halachic Regulation of Behavior

Should drugs be legal? What about prostitution? With regards to secular law, it surprises some to realize that law is used as a behavioral tool. If we can't stamp out prostitution, perhaps we should minimize it. We can do that by legalizing and regulating it. The same with drugs, instead of giving jail time, we should regulate their use, thus minimizing overall drug use.

This approach isn't without debate. A society that regulates prostitution, is a society that allows for prostitution. Minimizing it is a cop out, a compromise of ideals.

How does Halacha use the same tools? Or does it? Halacha forbids prostitution, and I can't see it being "regulated" so that it can be minimized. But what about loans for shemittah? Or workarounds for ribis? What are other examples where halacha imposes rules (takanos) to protect other rules, minimize those which aren't acceptable, or allows for workarounds to "further" societal goals?