For conspiring with the NSA to violate its privacy contracts with its customers:

The government requires the collaboration of major
telecommunications companies to implement its unprecedented and illegal
domestic spying program.

AT&T Corp. (which was recently acquired by the new
AT&T, Inc,. formerly known as SBC Communications) maintains
domestic telecommunications facilities over which millions of
Americans’ telephone and Internet communications pass every day. It
also manages some of the largest databases in the world, containing
records of most or all communications made through its myriad
telecommunications services.

The lawsuits alleges that AT&T Corp. has opened its key
telecommunications facilities and databases to direct access by the NSA
and/or other government agencies, thereby disclosing to the government
the contents of its customers’ communications as well as detailed
communications records about millions of its customers, including the
lawsuit’s class members.

The lawsuit also alleges that AT&T has given the government
unfettered access to its over 300 terabyte "Daytona" database of caller
information — one of the largest databases in the world. Moreover, by
opening its network and databases to wholesale surveillance by the NSA,
EFF alleges that AT&T has violated the privacy of its customers and
the people they call and email, as well as broken longstanding
communications privacy laws.