 Walter HustonAmbassador Joseph E. Davies | Ambassador Joseph E. Davies |
 Ann HardingMarjorie Davis | Marjorie Davis |
 Oskar HomolkaMaxim Litvinov | Maxim Litvinov |
 George TobiasFreddie | Freddie |
 Gene LockhartViatcheslav Molotov | Viatcheslav Molotov |
 Eleanor ParkerEmlen Davies | Emlen Davies |
 Richard TravisPaul | Paul |
 Helmut DantineMaj. Kamenev | Maj. Kamenev |
 Victor FrancenVyshinsky, chief trial prosecutor | Vyshinsky, chief trial prosecutor |
 Henry DaniellMinister von Ribbentrop | Minister von Ribbentrop |
 Barbara EverestMrs. Litvinov | Mrs. Litvinov |
 Dudley Field MaloneWinston Churchill | Winston Churchill |
 Roman BohnenMr. Krestinsky | Mr. Krestinsky |
 Maria PalmerTanya Litvinov | Tanya Litvinov |
 Moroni OlsenCol. Faymonville | Col. Faymonville |
 Minor WatsonLoy Henderson | Loy Henderson |
 Vladimir SokoloffMikhail Kalinin, USSR president | Mikhail Kalinin, USSR president |
 Maurice SchwartzDr. Botkin | Dr. Botkin |
| JJoseph E. DaviesSelf - in Prologue | Self - in Prologue |
| EErnst HauessermannShip's Steward | Ship's Steward |
 John AbbottGrinko (uncredited) | Grinko (uncredited) |
 Ernie AdamsHeckler (uncredited) | Heckler (uncredited) |
| EEd AgrestiSecond Trial Judge (uncredited) | Second Trial Judge (uncredited) |
| AAlex AkimoffO.G.P.U. Man (uncredited) | O.G.P.U. Man (uncredited) |
 Fred AldrichMan at Bar in Montage (uncredited) | Man at Bar in Montage (uncredited) |
| DDemetrius AlexisO.G.P.U. Man (uncredited) | O.G.P.U. Man (uncredited) |
| EElizabeth ArcherElderly Woman (uncredited) | Elderly Woman (uncredited) |
| LLouis V. ArcoTrain Announcer (uncredited) | Train Announcer (uncredited) |
 Sam AshAmerican Senator (uncredited) | American Senator (uncredited) |
| HHerbert AshleyElectrician at Madison Square Garden (uncredited) | Electrician at Madison Square Garden (uncredited) |
