Paul Mazursky gave us three fine films: Blume in Love, Harry & Tonto and Moscow On the Hudson, and a host of lesser works that we can still enjoy. I can't think of many American directors of the last half-century with a record like his. Blume In Love is obviously influenced by Truffaut's Jules and Jim, but is funnier, faster and not indebted to literary models as Truffaut's film was.
The triangle of Blume, Nina and Elmo works so well because of Kris Kristofferson's easy charm and rock star charisma. The story would have foundered on Blume's obsessiveness and Nina's Puritan desire to do good ("I haven't done much for the farmworkers, but I boycott the supermarkets") had Elmo not been around to keep things light. The story he tells of the bust in Franklin, Tenn. is wonderfully funny, although a little scary, and the trio's singing Chester the Goat is a delight.
I became a George Segal fan when I first saw this movie, and I can't help but lament the lack of intelligence and depth in today's actors when I see what he does with this difficult character. Marsha Mason is his equal in talent, playing Arlene, Blume's vulnerable lover who knows her days are numbered. The smaller roles are ably filled, particularly Shelley Winters as the woman whose husband left her.