"The searches were permissible due to Section 702 of the Foreign Intelligence Surveillance Act, which was originally passed in 1978.
Section 702, which is due to expire next year, was added to FISA after the September 11, 2001 terror attacks. "
There's more explanatory info in the article you failed to read or comprehend...but to list them here would be casting too many pearls before you.
(no message)