The trivia item below may give away important plot points.
Exactly a decade earlier, Dana Andrews also played a reporter spying for America and is imprisoned at one point in the movie, titled Berlin Correspondent. That was about World War II while this is set during The Cold War. Both films centered on wars happening at the time of filming and release. Also, both characters randomly announce seemingly normal news reports with certain words having hidden meanings (like riddles) for his side to figure out. Then the enemy manipulates his voice to make him seem in cahoots with them. And they eventually sentence him to death (and he escapes). Also, he loves a woman who another man loves, and another woman loves that man. There's an old man in peril that Dana helps. All in all, the two films are extremely similar.