Congress is grappling with renewal of a surveillance law set to expire at the end of this month that critics say is a mystery on how much of a difference it has made for controversial government spying authorities — for better or worse. The 2024 law reauthorized so-called Section 702 powers of the Foreign Intelligence Surveillance Act (FISA), which authorizes warrantless surveillance of electronic communications of foreign targets. Most controversially, the law allows U.S. officials to search (“