Thanks for the correction.
The Story of United States v. United States District Court (Keith): The Surveillance Power
Columbia Public Law Research Paper No. 08-189
Trevor W. Morrison New York University School of Law
November 20, 2008
FISA was expanded in the wake of 9/11/2001, but mostly in the areas of bulk data collection (what Snowden revealed to the public) and national security letters, another form of warrantless snooping.
I'm of a mind that Trump and members of his campaign were snooped with no warrant, long before the Steele dossier came around. Evidence of this is the wanton "unmasking" by Samatha Power and contractors for the FBI noted in the FISC opinion of April 2017.