For a 70's TV movie, this is strong stuff. Katherine tells the story of a pampered, UMC, boomer-princess who gets the virus of guilt when she is confronted with injustices in the third world and, you guessed it, turns Marxist.
I sound flippant here, but you can just guess the depths of depravity Sissy Spacek's Katherine--within the bounds of TV sensibilities--goes in her radicalized zeal to tear down the capitalist, fascist, materialistic, racist, showered and shaved system. And yet, when she is confronted with her lover's (Henry Winkler) using of revolutionary principles to justify his banging other girls, you can see her losing her last shred of sanity, her desire to someday have marriage to enjoy and family to care for. The transformation of Katherine from seeker of justice to angry, depraved killer is heartbreaking.
Spacek shows the sort of talent that has made her such a seriously good actress, Winkler is a journeyman actor himself (and you learn to hate him as his idealism morphs into something darker), Art Carney and Jane Wyatt are excellent as Katherine's good Democrat parents who enable her radicalization by funding their daughter as she dives deeper into the underground, and the rest of the supporting cast enriches the story.
The only drag on Katherine is the fact that it is a TV Movie (although the version I saw had a few moments of violence, drugs, and semi-nudity added; presumably for a theatrical release in Europe?). The film just doesn't have enough time to completely tell the story of the radicalized 60's and early 70's. Even though it's told in flashbacks and documentarian interviews (and the interviews with Spacek are so chillingly peaceful, you suspect there's something really bad coming), the time constraints truncate the story. You're left with an almost-told story, not a complete one.
Yet, the strength of the performances and the topicality of the story keep Katherine alive, watchable, and ultimately, crushingly sad.