Limewire has struck back against the RIAA, alleging that the RIAA is engaged in antitrust violations, consumer fraud, and "other misconduct". Limewire asserts that the RIAA's "goal was simple: to destroy any online music distribution service they did not own or control, or force such services to do business with them on exclusive and/or other anticompetitive terms so as to limit and ultimately control the distribution and pricing of digital music, all to the detriment of consumers."
I'm sure everyone believes that most of the content on Limewire, like most other p2p file sharing services, is copied without regard to the desires of the copyright holder. Whether this is true or not, I have no idea. However, it's starkly clear that the RIAA is at least as much interested in killing p2p as a distribution channel as it is about enforcing its members' copyrights. There is an equitable doctrine called "unclean hands" that seems to have some application here, but of late it seems that one can wash one's hands clean on anything if one has enough money to do it.