The film plays most effectively — which is not quite to say that it plays effectively — as a story of two couples, Lee and Marina (a Russian-speaking Michelle Trachtenberg), drifting part, and Jack and Jackie, coming together. As the less well-documented, less fabulous pair, there is more room to move with the Oswalds, for the writer and the actors to make them their own. (Trachtenberg has the least-thankless job here; most viewers will have no conception of Marina to measure her against.)
Marina Nikolayevna Oswald Porter (née Prusakova; Russian: Марина Николаевна Прусакова on July 17, 1941) is the widow of Lee Harvey Oswald, the alleged assassin of U.S. President John F. Kennedy. She married Lee Oswald during his temporary defection to the Soviet Union, emigrating to the United States with him. She was not implicated in the assassination and remarried following Lee Oswald's death.