Can You Sue a Communications Protocol?

Following news of Hollywood’s assault on p2p, Ed Felten wonders, a propos of hypothetical litigation over BitTorrent,

It’s hard to see how one could sue BitTorrent. How do you sue a communications protocol? You can sue the person who designed the protocol, but the protocol itself can’t be undesigned. Nor can the technical community unlearn the lessons it has learned.

There’s some Candyman-like idealism in that comment, even though it sounds right. But I don’t think that anyone would need to sue a protocol, if shutting down BitTorrent were really the goal.