If a government agency collects private data for one purpose, and then another agency searches through it to try to detect unrelated criminal activity, wouldn't that violate the Fourth Amendment? Or at least some sort of data privacy laws?
Can the IRS pull credit reports of everyone with an FHA mortgage to search for tax evaders? <shrug>
Oops -
looks like I'm wrong:
Following the controversial Passenger Name Record agreement signed with the European Union (EU) in 2007, the Bush administration provided an exemption for the Department of Homeland Security and the Arrival and Departure System (ADIS) from the U.S. Privacy Act.[7] ADIS is intended to authorize people to travel only after PNR and API (Advance Passenger Information) data has been checked and cleared through a US agency watchlist.[7] The Automated Targeting System is also to be exempted.[7] The Privacy Act does not protect non-US citizens, which is problematic for the exchange of Passenger Name Record information between the US and the European Union.