Politico reports that the Justice Department wants Congress to make Internet service providers store data about their users for a specified length of time to facilitate federal investigations:

Current law doesn't require those Internet service providers to "retain any data for any particular length of time," although some already do, said Jason Weinstein, deputy assistant attorney general at the DOJ's Criminal Division. And many wireless companies — which must collect some data — also "do not retain records that would enable law enforcement to identify a suspect's smartphone based on the IP address collected by websites the suspect visited," he noted in prepared testimony.

That's why Weinstein urged the Senate Judiciary's Privacy, Technology and the Law subcommittee on Tuesday to consider data-retention legislation as it weighs new privacy efforts in the digital age. The top DOJ official said such a congressional fix would boost the agency's ability to investigate privacy breaches, prosecute other digital crimes and ferret out abuses in the offline world.

"Those records are an absolutely necessary link in the investigative chain," Weinstein told the panel.

I don't doubt that the information could be useful to government investigators. Does that fact justify forcing companies to retain it? Such a mandate goes beyond the customary assistance that businesses are required to give in response to a court order. As with the Clinton administration's Clipper chip proposal, the defunct ban on exporting strong encryption software, and the Communications Assistance for Law Enforcement Act (a.k.a. CALEA, which requires telecom companies to make their networks tap-friendly), the government wants to arrange the world to make life easier for law enforcement agencies. Once we accept this demand as legitimate, the only question is how to "balance" privacy interests against the enhanced security promised by unimpeded policing—an inherently subjective judgment that tends to favor the government, since cops can always cite concrete examples of how they would use their new powers for good, while the negative implications seem vague and hypothetical.

Opponents of the Clipper chip, an encryption system with a government-held key that the Clinton administration wanted to mandate for telecommunications, used to ask whether we should all be forced to hand over our house keys to the local police, just in case they need them, or keep our window blinds up at all times to facilitate government surveillance. If those demands are unreasonable, why is it OK to insist that our ISPs keep track of us and save the records, just in case the government wants them? The argument for CALEA was that the government just wanted to keep the capability it historically had to listen in on phone conversations upon obtaining a warrant. Yet the statute now applies to email and other forms of communication that did not exist when wiretap law was developed. Likewise the DOJ's new legislative proposal. Why assume that Internet users must be trackable simply because phone lines used to be tappable?