Imagine you're suspected of committing a crime and that police want to track your whereabouts based on cellphone data from your wireless service provider without first getting a warrant. Guess what? They already can.

Few people are aware of this fact beyond police, criminal defense attorneys, lawmakers and privacy advocates, but if a bill currently being discussed on Capitol Hill eventually passes, the law could make it harder for law enforcement to monitor people without any judicial oversight. The Geolocational Privacy and Surveillance Act would require law enforcement to get a search warrant before getting cellphone data that can track the user's location. Colorado and most other states lack any statute that clearly governs how police can and should access this information, even though earlier this year five U.S. Supreme Court justices suggested that using this data could violate Fourth Amendment protections against illegal search and seizure.

Cellphone service providers usually are able to track two types of cellphone location data: real-time and historical. As cellphones and towers exchange signals every few seconds, cellphone providers can pinpoint a phone's movement -- and that of the person carrying it. Most service providers keep the historical data for a year or more. Representatives from the American Civil Liberties Union and cellphone service providers told the House Subcommittee on Crime, Terrorism and Homeland Security, which is debating the bill, that analysis of this data can easily tell trackers about the cellphone user's life through their comings and goings.

The bill has its opponents, of course, namely among law enforcement and prosecutors. A Maryland state's attorney argues that the GPS Act could limit the ability to quickly obtain important information, thereby weakening law enforcement efforts to protect citizens. Police would need probable cause to obtain a warrant before tracking a suspect, which could cost detectives valuable time.

The GPS Act still has a long way to go before it becomes law, if it eventually does. In the meantime, it pays to be aware that if police have any reason to track your whereabouts, they don't need to get a judge's approval to do it.

Source: The Blog of Legal Times, "At Hill Hearing, Law Enforcers, Privacy Advocates Debate Cell Phone Data Bill," Todd Ruger, May 17, 2012