[0] https://en.wikipedia.org/wiki/Data_Protection_Directive
[1] https://en.wikipedia.org/wiki/International_Safe_Harbor_Priv...
Magically, should a bill/resolution be introduced to the floor and not be stomped on immediately, enforcing it internationally would be about as difficult as say, enforcing international oil embargoes or a ruling by the ICC (i.e., nearly impossible - you don't see any proceedings against Cheney or Rumsfeld for war-crimes within the Hague, now do you?). Domestically, however, the US has (or had, historically from, say, 1930 until the mid 90s) the economic/political influence to effectively enforce their agendas fairly effectively. The new US gov't entity formed would have to have the intent to limit data collection then exhibit the willingness to penalize those institutions for violating those data collection policies (e.g. similar to an FDA fine issued for a multi-national drug company who has a presence within the US).
Again, too many financial interests opposed to see this happening, but the refusal to adhere to the legislation would mean (in theory) loss of US business, which would be catastrophic for most industries. HackerNews user:grellas (or was, I haven't seen him post in a couple years now) is an attorney specializing in tech affairs who'd be able to make a better response, but from a strictly political POV, even domestic legislation limiting data collection would never occur.