Answer: deepthroat

AnswerCrossword Clue
DEEPTHROATWoodward's anonymous informant
DEEPTHROATInformant some say was Pat Buchanan
DEEPTHROATWatergate figure whose real name is Mark Felt
DEEPTHROATWatergate figure
DEEPTHROATFamed Watergate tipster
DEEPTHROAT"All the President's Men" figure
DEEPTHROATSource for Woodward