The California Supreme Court has ruled that police don't need a warrant to search the text messages on a cell phone being carried by a suspect.

The 5-2 decision in People versus Gregory Diaz, released Monday, affirmed an appeals court decision in a case involving an arrest for alleged drug dealing in 2007. Diaz, the defendant in that case, had appealed his conviction on the basis that the search violated the U.S. Constitution's protection against unreasonable search and seizure.

Diaz was arrested in 2007 on suspicion of conspiring to sell the drug Ecstasy to a police informant. When he was arrested, police found six tabs of Ecstasy and a cell phone on his person. Going through the sent text messages that were still stored on the phone, the police found the message "6 4 80," which a Ventura County deputy sheriff interpreted as a proposal to sell six tabs of Ecstasy for US$80. When confronted with this evidence, Diaz admitted participating in the drug sale.

The majority opinion, written by Justice Ming Chin, cited precedents from the U.S. Supreme Court, saying the contents of a cell phone are like the contents of clothing or a cigarette pack found on a suspect's person. The U.S. Supreme Court has found that those types of searches do not require a warrant under the 14th Amendment to the Constitution, the court said.

In a dissenting opinion, Associate Justice Kathryn Mickle Werdegar wrote that cell phones are different from the personal items involved in the earlier cases because of the large amount of information that can be stored on them. "Never before has it been possible to carry so much personal or business information in one's pocket or purse," Werdegar wrote.

Stephen Lawson covers mobile, storage and networking technologies for The IDG News Service. Follow Stephen on Twitter at @sdlawsonmedia. Stephen's e-mail address is stephen_lawson@idg.com