The Parallax View (1974) IMDb
Seen in 2015.
A few great scenes and just a hint of science fiction, not too far from the reality of programs like MKUltra, which was secretly terminated while the film was being made. Marred by silly fisticuffs, an overly competent hero and Hitchcockian coincidences to drive the plot. This would work wonders to set the mood for a cowboy-era game of Delta Green, but it is gloriously specific to its cultural moment.