The U.S. Senate Friday ratified an international treaty designed to ease investigation of cybercrime, but U.S. civil liberties groups say that signing the pact is a big mistake.

The Council of Europe's Convention on Cybercrime, which began circulating in 2001, has been adopted by 41 other countries, including most of Europe as well as Canada and Japan. It is designed to harmonize laws on computer crime, which differ from country to country.

Countries that sign the treaty agree to establish some common laws against criminal behavior online, such as attacks on computer networks, terrorist tactics, and exploitation of children. The language of the treaty is very broad and doesn't require the U.S. to write any new cybercrime laws.

However, by signing the treaty, the U.S. will now be bound to aid its partner countries in the investigation of cybercrime, even if the alleged perpetrators have not violated any U.S. statute, critics say. The American Civil Liberties Union and the Electronic Frontier Foundation (EFF) both called the treaty the "world's worst Internet law."

"Countries that have laws limiting free speech on the Net could oblige the FBI to uncover the identities of anonymous U.S. critics, or monitor their communications on behalf of foreign governments," the EFF said. "American ISPs would be obliged to obey other jurisdictions' requests to log their users' behavior without due process, or compensation."

However, Council of Europe documentation on the treaty suggests that the EFF may be oversimplifying the treaty's position on ISPs. "Service providers are obligated only to preserve (i.e., not delete or disclose) data that they are currently storing, if requested to do so by law enforcement with respect to specified data in a particular case," the Council says. ISPs aren't required to retain or disclose data not needed for business purposes, it says.

Still, critics are concerned about the mandate for U.S. law enforcement agencies to investigate crimes on behalf of other countries. "A future leftist President could even allow Communist China to sign on to the treaty and direct U.S. law enforcement to investigate Chinese dissidents, even Americans, based in the United States," postulated one critic.

But U.S. law enforcement agents are happy about the treaty, because it will help them to investigate cybercrimes launched from other countries. The pact will help law enforcement agencies to obtain electronic evidence needed to prosecute cybercrime cases, says U.S. Attorney General Alberto Gonzales.

— Tim Wilson, Site Editor, Dark Reading