  To see the second point, consider the possession of guns. Possessing a gun is not itself harmful. And many possess guns without unreasonably risking harm. If one endorses (HCP), one must either weaken one’s chosen principle or accept that gun possession cannot be criminalized.  If one endorses (HPP), things are different. What matters is not the effect of each instance of gun possession, but the effect of criminalizing all of them: if criminalizing possession will prevent harm that would not otherwise be prevented—and do so at a not disproportionate cost—the fact that some owners possess guns safely is beside the point. Whether or not (HCP) is satisfied, (HPP) is.