If the news reports are accurate, authorities knew very little, if anything, about the couple who shot up the county party room in San Bernadino. More likely, those two were somewhere in the files but buried under mountains of data about everyone else.
The NSA domestic surveillance program that recently expired didn't do anything to prevent it. The program's only obvious use so far is to put together histories after a crime. While that's helpful, it still doesn't justify the mass surveillance.
So maybe the president and others will stop whining about how law enforcement hands are tied by the requirement that they have to go to the FISA court for authority to get telephonic meta data.