John Cassavetes did not receive an Oscar nomination for portraying Robert Harmon in Love Streams.
Any my focus though is on Cassavetes as the actor not the director, and though he's perhaps viewed as an acting director these days he technically is an actor turned director despite having few prominent roles before his transition. This is actually one of his final performances as a director the role of Robert who we are introduced to as a playboy writer. Cassavetes isn't not an excessively charismatic performer, and there is something rather odd about casting himself in the role. The reason being Robert is the brother of Sarah played by Gena Rowlands's the wife of John Cassavetes. Although perhaps this is to show the undisputed closeness of the siblings not even in a romantic way, though the initial kiss upon meeting might be a touch too comfortable for non-Lannister siblings. Still that isn't exactly the focus, and it is not where the film starts. The film begins with Robert living his life which is that of slight relationships with only the occasional more substantial one when it is thrust upon him.
Cassavetes is more than convincing as the pleasure seeker in Robert as a man who just goes around looking for something to enjoy whether it is a drink or a woman. Cassavetes's performance sort of conveys this idea of an attempt of joy. In that there is always this intention and energy of someone trying to have a good time, even though he is not exactly always wholly capable in this regard. Cassavetes is good though in that he plays the part as though Robert is either just slightly tipsy or just has a bit of a hangover. Cassavetes is effective in realizing this day to day state of Robert as never exactly becoming too associated with anything. The film though decides to actually ram through his story rather quickly by having Robert suddenly having to deal with his son who is brought over by his estranged wife. Again the pacing of this element seems rather rushed, given how slow paced the film is in general. Cassavetes impresses himself to make something out of this in very short time. Cassavetes sort of does in just playing it as general frustrations of dealing with something that leaves him a little uneasy.
The film wraps that facet up and moves mostly to focusing on dealing with the mentally unstable Sarah who just commits one strange behavior after another. Cassavetes in the interactions between Robert and Sarah though suggest a bit of a different side to Robert. In that Cassavetes is rather good in at least portraying basically a loving brother's understanding of his sister in that he never reveals too rash of reaction, spelling out years of knowing her madness. Cassavetes doesn't limit this still showing that Robert is taken aback but holds back these frustrations to lashing out against her. Cassavetes is able to convey the complexity of that relationship and his performance works in that regard.. I have to say though his and Rowlands's performances work they never added to anything more than fulfilling the base need of to be a "good performance". Unlike A Woman Under the Influence and Faces this film never had a real emotional resonance. It felt more like acting for the sake of acting, behavior for the sake of behavior, uncomfortable situations simply to be uncomfortable situations. Now that acting for the sake of acting doesn't mean bad acting. In Cassavetes and Rowlands are both good in their roles, but their work simply laid there at a distance. Admirable in technique, but not engaging in terms of either crafting a truly empathetic or compelling character.