The Candidate (1972)

Michael Ritchie made a number of interesting films in the 70's (he also made some real duds) and this is one of them.  With a particularly literate script which won an Oscar, it tells the tale of an idealistic young lawyer (Robert Redford) who is cajoled into running for office as the senator from California by a devious Peter Boyle on the grounds that he can not possibly defeat the incumbent.  He therefore feels free to speak his mind on the various issues rather than play politics as his father (Melvyn Douglas) did before him. His refreshing approach results in his victory and it is only then that he realises that he has no idea whatsoever as to what he has taken on.  For once one could actually see Redford displaying real emotion in his puzzlement.