Decriminalization would increase the use and the economic and social costs of drugs.

In fact, the benefits of keeping marijuana and other illicit drugs illegal clearly outweigh the negative and predictable consequences of legitimizing these substances.
Our position is simple and evidence-based: both decriminalization and legalization of illicit drugs would increase their use, along with their associated health and social costs. Unless advocates of decriminalization or of outright legalization can establish that more drug use is a net good for society, both arguments are self-refuting.
Higher prices help hold down rates of usage.