NO MATTER what the “content-should-be-free” crowd says, copyright theft robs artists and businesses of their livelihoods. Creative industries employ millions of people in the advanced world (and could be a rung on the ladder for poorer countries too, if, say, unscrupulous European content thieves did not habitually purloin the efforts of African musicians). The damage may be less than the annual $135 billion that the entertainment and publishing industries claim. These firms could change their business models to reduce the pirates' profits, especially in countries where an album costs a day's wages. But mispricing does not justify crime.

So far, attempts to stop online piracy have largely failed. Lawsuits did shut down file-sharing services such as Napster and Grokster, but others have taken their place—such as Pirate Bay and the new “cyberlockers” (see article) that operate in hard-to-reach jurisdictions. Many users of these sites think they are swapping, not stealing, material. But the cyberlockers make money with extra charges for heavy users.

Congress is now considering the Stop Online Piracy Act (SOPA) which would let copyright-holders take action against the intermediaries—such as payment services, search engines, and internet service providers (ISPs)—that supply money and traffic to pirate sites. If the intermediaries do not cut these sites off, they will face lawsuits.

In principle, the move is a good one. Content companies need more effective legal remedies against piracy. And the thrust of the bill is sensible. Search engines direct users to pirated content and make money off the ads that appear next to the search results. The threat of lawsuits might encourage them to do much more to ensure that a search for, say, “Lady Gaga mp3 download” brings up legitimate online music services only. And putting the burden of enforcement on the private sector has advantages: the aggrieved party will have a better idea than the state whether a copyright infringement is worth pursuing.

But the bill has problems too. The loose definition of infringement in SOPA could include sites that unwittingly carry comments linking to pirated material. That would make it too easy to launch spurious claims and too onerous for intermediaries to deal with them, and could discourage entrepreneurs from setting up new sites allowing users to post things (which, in the era of social media, is almost all websites). Large firms can cope with the extra hassle, but the fear of lawsuits could stifle smaller companies and start-ups.

A second big drawback is that SOPA obliges ISPs to put filters in place to prevent their customers reaching pirate websites easily. That risks damaging the internet's vital internal addressing system, which lets people use words instead of numbers to access websites. It also clashes with DNSSEC (don't ask), a protocol that America has long championed to increase internet security. Messing with DNSSEC could create loopholes for hackers by allowing rogue websites to pose as legitimate ones. Savvy users (who do the most downloading) will be able to bypass these filters anyway. And the bill's vague wording leaves open the possibility that American ISPs might have to institute more intrusive forms of filtering, with the costs, performance problems and privacy issues that would inevitably entail.

More selective, more effective

Yet SOPA's flaws are not, as its opponents claim, fatal. The bill should be pruned and tightened—by defining more narrowly the kinds of websites that intermediaries can be asked to block, and by removing the requirement that ISPs put filters in place—to ensure that it makes life harder for malefactors without damaging the internet or imposing unreasonable costs on the law-abiding.

The battle over SOPA is a fight between two hugely creative forces. The content companies want to protect a business that is the core of modern culture; the software companies are determined to defend the innovative power of an industry that has transformed the world in the past few decades. Tension between them is inevitable; but a redrafted law could surely deal fairly with both.