[rl3]

>If the NSA could force Google to hand over anything, why were there Snowden slides showing that the NSA was secretly tapping Google's internal networks?

First, they can force Google to hand over anything. NSLs and the PRISM program are evidence of this, and both are relatively narrow in scope. However, each time the feds compel a top-tier tech corporation like Google to cooperate, the entire thing is scrutinized by lawyers on both sides, and risks drawing the ire of pissed off employees. There's probably many more potential Mark Kleins in Google than there are at a telecom like AT&T—the latter company's relationship with the NSA being best categorized as incestuous.

That being the case, why conduct bulk data collection overtly when they can do it covertly? The aforementioned overt measures ensure prompt data access in the event of an emergency, and keep everyone thinking they're on the up and up. Meanwhile, the truly nasty stuff like domestic bulk collection is conducted behind the scenes.