Oskar Werner did not receive an Oscar nomination, despite winning the Golden Globe and being nominated for BAFTA, for portraying Fiedler in The Spy Who Came in From The Cold.
Fiedler is an east German intelligence agent who interrogates the falsely disgruntled British agent Alec Leamas (Richard Burton). It's a technically friendly interrogation as Leamas has been made out to be a fake traitor to give Fiedler misinformation to take down his superior Mundt as a British agent. Werner seems to have a simple enough role as Fiedler begins to derive his information from Leamas. What Werner does so well is give a great deal of life to Fiedler through the margins. Werner conducts himself brilliantly in these scenes doing so much through the smallest moment. For example when Leamas mentions Mundt was a former Nazi to the Jewish Fielder, Werner's reaction is pure perfection. He reacts as a man with this knowledge already but there is a discontent within in this even though he feigns not caring not to lead on to Leamas that he has a problem with Mundt. It's a great piece of acting by Werner but every second of his scenes with Burton are great as he gives so much character to Fiedler in every little reaction he makes.
There is such a likability that Werner brings as he goes through the questions as Werner presents Fiedler to be essentially an honest man in a profession entirely made up of dishonest people. Werner shows a man who is actually genuine as he tries to deal with Leamas in a respectful way even though Werner still conveys the proper intrigue and intelligence as Fielder slowly deciphers the information. It an interesting trick Werner pulls here as Fiedler could have just been there to be a plot point, but Werner does so much more than that in this scene. His performance stands separately from almost every other performance in the film because Werner presents a man who says who he is. There are things he covers up for sure such as his dislike for Mundt, but Werner portrays this as something he has to do rather than something he truly wants to do. Werner does such a fantastic job of establishing Fiedler, and even creating a sympathy for the man that he makes his final scene something truly special.
The last scene is a trial in front of a East German tribunal where Fielder presents the information, false information he got from Leamas, to incriminate Mundt as a traitor. Werner is outstanding as Fiedler gives his case to the court as he brings so much passion in his pleading to the courts to sentence Mundt for having betrayed the cause. It's fascinating what Werner does in that he shows us the only true believer, which happens to be the enemy cause, but it's hard not to feel for him because Werner presents Fielder's as true to that cause, unlike every other man we see in the spy game. The only moment that trumps the power of that scene though is when the court learns of the British plot to set up Mundt revealing that they were only using Fiedler. Werner is heartbreaking as he shows the utter disbelief and shock as the truth comes out. In Werner's face you can see a man who knows he's suddenly just lost his life. This is marvelous work from Werner as he does something really quite interesting that was absolutely up to the performance. Fiedler is the whole target of the spy trick set up by British Intelligence, but when it is executed it is not a pleasant feeling elicited. Werner's performance creates the brutality of the espionage because he so wonderfully humanizes this enemy, and presented a tragic man who doomed himself by only doing what he thought was right.