he future is demonstrated even more eloquently by the furor surrounding America Online's acquisition of Time Warner. Many experts warned that the merger would create an Internet juggernaut, in which the combination of America Online's Internet content with the transmission capabilities of Warner Cable would chill innovation and with which other providers would struggle to compete. Needless to say, these dire predic- tions failed to materialize, as the vertically integrated business model that America Online pursued with such confidence ultimately proved to be a colossal failure. the absence of some reason to believe that policy makers will be able to anticipate which architecture will ultimately emerge as optimal, mandating one architecture over another has the unfortunate effect of foreclosing exploration of the potential benefits of alternative approaches. Fortunately, competition policy offers a middle ground that obviates the need for policy makers to make such judgments. If the choice between two architectural approaches is ambiguous, policy makers have the option of permitting both alter- natives to go forward until concrete harm to competition can be demonstrated. In other words, rather than mandating any particular architecture, policy makers can instead embrace a regime of network diversity that allows network owners to pur- sue different strategies. Unless such experimentation poses potential harms that are catastrophic or irreversible, the emerging consensus argues against imposing proac- tive regulation on the basis of speculation about the likely impact on competition (Sunstein 2005). This approach places regulators in a more restrained and humble position that is better suited to their institutional capabilities. Rather than asking them to determine which architectural design is likely to prove more socially beneficial, it asks them only to determine whether a plausible case can be made to justify each possible approach and whether allowing experimentation with each approach would pose potentially c