Update (April 25): The Leahy-Lee bill was The Leahy-Lee bill was approved by the Senate Judiciary Committee on Thursday. The original story on this initiative appears below.

If the police want to read copies of a snail-mail letter you've received, they generally need to get a warrant. But the situation is different for e-mail. Under the terms of the 1986 Electronic Communications Privacy Act, e-mail older than six months is considered abandoned. Authorities can obtain copies of it with no judicial oversight.

When Congress established this rule, modern cloud e-mail services were still far in the future. Network storage was expensive, so it was assumed that users would delete messages from servers after reading them. Today, of course, people routinely leave years worth of e-mail sitting on the servers of webmail providers, making them vulnerable to government snooping.

The need for reform has been obvious for years, but recent events have created a greater sense of urgency. On Thursday, the Senate Judiciary Committee will meet to "mark up" a bill to reform ECPA. The House Judiciary Committee held a hearing on e-mail privacy last month.

Ars talked to Chris Calabrese, an attorney at the American Civil Liberties Union, about the privacy proposals Congress is considering. He told us that the leading proposals would affect much more than e-mail.

The legislation under consideration in the Senate was proposed by Patrick Leahy (D-VT), the chairman of the Judiciary Committee, and Mike Lee (R-UT), a senator with strong ties to the Tea Party. Calabrese told us that the Leahy-Lee bill "would require a warrant for all private electronic content. So it's e-mails, it's texts, Google Docs, it's photos in Picasa, it's private social networking posts."

Right now, under the so-called third-party doctrine, "anything that's not a communication, like a Google Doc, is accessible with a subpoena." Calabrese argued that reforms were needed not only to protect Americans' privacy, but also to promote the growth of companies offering cloud-based services. He believes that documents stored on cloud-based services should enjoy the same robust Fourth Amendment protections as conventional paper documents.

The ACLU supports Leahy's bill, and Calabrese said he hoped the legislation could be approved by the Judiciary Committee on a simple voice vote. Sen. Chuck Grassley (R-IA), an influential Republican on the Judiciary Committee, has expressed support for the legislation.

"I have long believed that our government should obtain a search warrant—issued by a court—before gaining access to private communications," Leahy said last week, according to The Hill. "I have worked over the last several years to update our federal privacy laws to better safeguard our privacy rights in the digital age."

E-mail privacy is also being considered by the House of Representatives. Rep. Zoe Lofgren (D-CA) has introduced legislation with Rep. Ted Poe (R-TX) that would beef up privacy protections for both e-mail and location tracking.

Location tracking is the subject of a separate hearing being held by the House Judiciary Committee on Thursday. In the Senate, a separate bill by Sen. Ron Wyden (D-OR) and Mark Kirk (R-IL) would increase legal protections for location privacy. Calabrese said it was unclear whether Congress would eventually pass a single bill addressing both issues, or whether they would be considered separately.