WASHINGTON--Patrick Leahy, the chairman of the Senate Judiciary committee, said today he is optimistic that Congress would update a 1986 law, crafted in the pre-Internet era of telephone modems and the black-and-white Macintosh Plus, to protect the privacy of Americans who use the Internet and mobile phones.

The Vermont Democrat said that in his previous career as a prosecutor he had to obtain search warrants to search someone's house. "I question whether it should be that much different if I'm going to search all your files" in electronic form, he said in a keynote speech at the Computers Freedom and Privacy conference here.

Last month, Leahy introduced legislation called the Electronic Communications Privacy Act Amendments Act of 2011 (PDF) that would, in many cases, require police to obtain a search warrant to access private communications and the locations of mobile devices. But one important exception maintains the status quo: it does not require a warrant for police to peruse your historical whereabouts obtained by recording the movements of your cell phone, even if the location data are only a few hours old.

After his speech, Leahy told CNET that the exception was included to address law enforcement concerns.

In April, the U.S. Department of Justice launched a frontal attack on the idea of requiring search warrants for locations, with James Baker, the associate deputy attorney general, telling a Senate panel that such a requirement--for either historical or live tracking data--would hinder "the government's ability to obtain important information in investigations of serious crimes." Previously, the department had argued in court that warrantless tracking should be permitted because Americans enjoy no "reasonable expectation of privacy" in their, or at least their cell phones', previous locations.

Leahy also told CNET that he hopes to gain Republican support. (His bill has no GOP supporters.) "I hope so," he said. "Otherwise we'll have a heck of a time passing it."

A related Senate location privacy proposal, introduced yesterday by Sen. Ron Wyden (D-Ore.), was slightly weakened over the last few months to attract Republican support. The final version of the bill deleted about nine pages of text that would have curbed foreign intelligence location collection. But it also gained a conservative Republican sponsor in the form of Rep. Jason Chaffetz of Utah.

The 1986 law in question, called the Electronic Communications Privacy Act, or ECPA, is notoriously convoluted and difficult even for judges to follow. Its labyrinthine wording means that currently, Internet users enjoy more privacy rights if they store data locally, a legal hiccup that some companies fear could slow the shift to cloud-based services unless it's changed.

In March of last year, CNET was the first to report the existence of the Digital Due Process coalition, composed of companies including Google, Facebook Microsoft, Loopt, and AT&T, along with liberal, libertarian, and conservative advocacy groups including the Electronic Frontier Foundation that have urged Congress to update the law.

The coalition has embraced four principles, including that a warrant signed by a judge should be required for the contents of communications and a warrant should be required to access location data. EFF has said that Leahy's bill fulfills 1.5 of those core principles.

Leahy also said his committee would hold a hearing next week on the administration's proposal for cybersecurity legislation released last month. The proposal aims to force companies to do more to fend off cyberattacks.

"I'm not going to say that any administration, Republican or Democratic, gets a pass," he said. "We have to respect our privacy rights, our civil liberties."