Assuming they don't just ignore the law (who's going to prosecute them, their buddies in the DA's office?) they can just get what they need from a fusion center

Assuming they don't just ignore the law (who's going to prosecute them, their buddies in the DA's office?) they can just get what they need from a fusion center or other federal or state partnership. Fundamentally, laws don't apply to cops, especially in the US, especially since 9/11.