OT:
Going to have to call ASB on this one ... the international event horizon for the Internet was in late 90s at which point nothing could stop it (except for some Y2K or Pluto's Kiss), and it was to big for one nation (even USA, even accounting for exceptionism) to stop globally dead prehaps even as early as September 93.
I'm guessing you'd have to stop Eternal September, and the similar more subtle event happening in Europe at roughly the same time (up to ~95), from happening ... Specially considering the competing interests nations between and the differing social mores, and specially in the OP's case, on Porn ... Whereas the American Evangelical Right would be hard pressed between deciding to run away screaming and setting it on fire, much of the more liberal europe (specially non-catholic europe, specially Germany, Scandinaiva and Benelux) have a much more laissez faire relation ship with such things, and would keep moving forward with no regards, and lots of mocking laughter, at America, as they'd be willing to accept quite a bit of porn on the internet to get what already then could be seen as strong compelling ideas and strengths ... It might move slower but that train is unstoppable by this point.
All that said, I'm relatively certain that the American Military would be aggessively against any idea of banning the Internet as they were the ones fronting the cash for large parts of the research needed, and also gained a lot from it, in terms of ease of communication specially.