bring the market back into long-run equilibrium (Yoo 2005). This tendency to forestall competitive entry implicitly presumes that rate regulation will persist indefinitely. Such a surrender to the monopoly only makes sense if competitive entry is infeasible. Mandating access to the existing network creates similar disincentives to invest- ments in alternative transmission technologies. Because any benefits gained from investments in capital or research must be shared with competitors, forcing a monopolist to share its resources discourages incentives to improve their facilities and pursue technological innovation. As Garrett Hardin (1968) pointed out in his path-breaking work on "the tragedy of the commons," resources that are in effect jointly owned tend to be overused and receive suboptimal levels of investment. Hardin's insights apply with equal force to compelled sharing of telecommunica- tions networks. In addition, denying providers of complementary services guaranteed access to the existing network gives them powerful incentives to enter into strategic partner- ships with firms interested in constructing alternative network capacity in compe- tition with the existing network. Using regulation to provide those same providers with guaranteed access to the existing networks would destroy any incentives to enter into such arrangements. In effect, forcing a monopolist to share an input rescues other firms from having to supply the relevant input for themselves. As a result, compelled access can have the perverse effect of entrenching any supposed bottleneck facility by forestalling the emergence of the substitute network tech- nologies. This is particularly problematic in technologically dynamic industries, in which the prospects of developing new ways either to circumvent or to compete directly with the alleged bottleneck are greatest. This analysis underscores the extent to which debates over access to networks have all too often focused on the wrong policy problem. One of the key insights of vertical integra