WASHINGTON, June 17, 2010  -- A unanimous Supreme Court todayruled that a southern California police department did not violate the constitution when it audited personal and sexually explicit text messages sent by one of its officers using an official pager.

Jeff Quon, the officer who filed the lawsuit against the Ontario Police Department, argued that department bosses violated his Fourth Amendment protection against unreasonable searches and seizures by obtaining and reviewing a transcript of his communications, even though the pager belonged to an employer account.

"Because the search was motivated by a legitimate work related purpose, and because it was not excessive in scope, the search was reasonable," wrote Justice Anthony Kennedy.

Quon believed he was following an informal policy at the police department when he sent personal text messages from his government-issued device. When he was confronted by his superiors about explicit emails he sent to his girlfriend, he sued, saying that his constitutional rights had been violated and that he had "reasonable expectations of privacy."

But the City of Ontario argued that it had initiated the search to determine whether the department had acquired a sufficient service contract with its text messaging provider and, in the process, encountered Quon's personal messages. During the search, Quon's supervisors realized that Quon had gone over his monthly allotment of messages because he was using the device for personal messages.

Lawyers for the city argued that when it acquired the pagers it announced a computer policy that applied to all employees, reserving the "right to monitor and log all network activity including e-mail and Internet use without or without notice."

Justice Kennedy acknowledged that the court was entering a new legal frontier in the information age and would proceed with caution before making a broad ruling on the privacy rights expectations of an employee.

"This court must proceed with care when considering the whole concept of privacy expectations in communications made on electronic equipment owned by a government employer," he wrote.

Kennedy said that the court was resolving the case on narrower grounds because a broad ruling concerning employees' privacy expectations while using employer-provided technological equipment "might have implications for future cases that cannot be predicted."

Supreme Court Rules Narrowly in Sexting Case

"Rapid changes in the dynamics of communication and information transmission are evident not just in the technology itself but in what society accepts as proper behavior," Kennedy wrote.

The case will provide guidance on employee rights versus employer rights at a time when employees are leaving an enormous trail of information through email, texts and wireless devices.