Except as provided in subsection (c) and to the extent consistent with due regard for the protection from unauthorized disclosure of classified information relating to sensitive intelligence sources and methods or other exceptionally sensitive matters, the General Counsel of each element of the intelligence community shall notify the congressional intelligence committees, in writing, of any significant legal interpretation of the United States Constitution or Federal law affecting intelligence activities conducted by such element by not later than 30 days after the date of the commencement of any intelligence activity pursuant to such interpretation.