All The President's Men (Alan J Pakula, USA, 1976)

allthepresidentsmen
Remarkably intelligent, working both as an effective thriller (even though we know the outcome of their investigations) and as a virtually abstract charting of the dark corridors of corruption and power.
— Geoff Andrew, Time Out

Based on the 1974 bestseller of the same name by Washington Post journalists Carl Bernstein and Bob Woodward. Dustin Hoffman and Robert Redford star, respectively, as Bernstein and Woodward, whose reporting of a break-in at the Watergate building (Democrat Party HQ) led to the discovery of corruption at the highest levels and ultimately brought about the resignation of President Nixon.