In January, Internet service providers will begin sending notices to subscribers suspected of illegally downloading music or movies using peer-to-peer file-sharing networks. After five increasingly sternly worded warnings, subscribers’ Internet access will be slowed down or partially blocked. This new “Copyright Alert System” is bound to raise the hackles of digital rights activists—but should it?

The system is the result of a private agreement between ISPs and the recording and movie industries. The agreement is nominally voluntary, although former New York Attorney General (now Governor) Andrew Cuomo strongly suggested to ISPs that they cooperate, and the Obama Administration’s IP czar Victoria Espinel helped broker the deal.

Under the new system, copyright holders monitor P2P networks and note the IP addresses of users they believe are engaging in piracy. The suspect IP addresses are passed along to the ISPs, which match them to individual subscribers, and then send the copyright nastrygrams. The ISPs never reveal to copyright holders the identities of subscribers.

The first two messages are “educational” warnings that merely let subscribers know that illegal downloading has been detected on their accounts. These will have an effect, for example, by alerting parents who are unaware that their kids are file-sharing. The next two warnings are more strongly worded and must be acknowledged by clicking on a pop-up before subscribers can continue to use their Internet connections. Users will never be cut off from the Internet completely.

With the fifth and sixth warnings, ISPs will implement a “mitigation measure” of their choosing, which might be slowing down access speeds, or blocking access altogether until the subscriber contacts the ISP. Before such a punishment goes into effect, subscribers will have an opportunity to appeal to a private third-party arbitrator by paying a refundable $35 filing fee and explaining why they think they are not liable.

The Electronic Frontier Foundation, among many other copyright skeptics, does not like the new program.

“Big media companies are launching a massive peer-to-peer surveillance scheme to snoop on subscribers,” a recent EFF blog post reads. “Based on the results of that snooping, ISPs will be serving as Hollywood’s private enforcement arm, without the checks and balances public enforcement requires. Once a subscriber is accused, she must prove her innocence, without many of the legal defenses she’d have in a courtroom.”

I don’t take a back seat to anyone in criticizing our out-of-control copyright system. Copyrights are too long and too strong, penalties for infringement are disproportionate, and federal enforcement has gotten out of hand. Yet those of us who seek to reform copyright should keep in mind that piracy is real, and copyright holders have a legitimate interest in enforcing their rights.

The EFF and others talk about surveillance and snooping, but in fact the monitoring in question takes place over publicly accessible networks. And while it’s true that the Copyright Alert System’s private arbitration flips the burden of proof, it’s not clear “public enforcement” is really such a great alternative.

One form of public enforcement is the kind of mass litigation the recording industry engaged in until recently, suing tens of thousands of Internet users in civil court. They sometimes unmasked the subscribers behind suspected IP addresses using subpoenas, and they made defendants an offer they couldn’t refuse: Accept a multi-thousand-dollar settlement or fight an expensive court battle that could potentially end in liability for hundreds of thousands of dollars. The other type of public enforcement is federal criminal prosecution, with disproportionate penalties and its own due process problems.

While the Copyright Alert System is far from perfect, it succeeds in treating illegal file-sharing as an infraction more akin to speeding, and less like grand larceny the way courts and prosecutors do. And the private system has its own set of checks and balances absent from public enforcement: ISPs have a strong incentive to ensure that their customers are not harassed by false positives or overzealous enforcement. (Indeed, the agreement limits the number of notices copyright holders may send in a month.) This is why the temptation to codify such a “six-strike” system in law the way France and other countries have should be resisted.

In the long run, the new system is likely to be ineffective at stopping piracy. Determined pirates will be able to detect and evade monitoring, spoof their IP addresses, or simply switch to other methods of file-sharing not covered by the agreement, like streaming or using locker sites or Usenet. In the short run, however, copyright alerts will attempt to nudge public norms that have increasingly moved toward widespread acceptance of file-sharing. Evidence suggests, though, that it’s probably too late for that too.

Rather than dismiss the new system out of hand, those of us seeking a saner copyright regime should welcome this experiment while keeping a close eye on it. If nothing else, it’s preferable to have content owners make constructive use of their private rights rather than rely on the power of the state.