In a written foreword, the film quotes the speech made by President Franklin Delano Roosevelt's at the Yalta Conference on 1 March, 1945: "Twenty-five years ago, American fighting men looked to the statesmen of the world to finish the work of peace for which they fought and suffered. We failed them then. We cannot fail them again, and expect the world again to survive." Dates of historical events were not mentioned in the film, although, as reported in Paramount News, an exact timetable of the events leading up to World War II was used on the set to enhance the "time consciousness" of the actors. Specific historical dates were added to clarify the above plot summary.
       One day before production began, HR listed screenwriter Peter Berneis as a dialogue contributor for the film; however, his contribution to the final film has not been confirmed by any other source. According to HR news items, Joan Crawford was considered for a starring role in the picture, and Leslie Venable, Mae Busch and Michael Strong were tested for roles, but did not appear in the final film. Paramount News lists Bill Meader in the cast as a reporter, but his participation in the released film has not been confirmed. Dudley Digges, who portrays "Moses" in the film, first played the part on Broadway. The film marked the screen debut of Douglas Dirk, and Robert Young's seventy-fifth feature. Director William Dieterle was borrowed from David O. Selznick's company, and actress Sylvia Sidney was borrowed from Cagney Productions. As reported in Paramount News, Viennese actor William Trenk, who plays "Ponette" in the film, was a popular comedian of the European stage, screen and radio before the war, and became a propagandist for the Austrian underground resistance movement. Before coming to the U.S., Trenk was imprisoned four times for lampooning Adolf Hitler. While in the United States, Trenk reportedly continued to send anti-Nazi broadcasts via short-wave radio to Germany and occupied Europe.
       Several reviews note that film changed the occupation of the stage character "Cassie" from a schoolteacher to a journalist. According to memos in the MPAA/PCA Collection at the AMPAS Library, early versions of the script included a consummated love affair between "Alex" and "Cassie" before his marriage to "Emily," as well as an adulterous affair later. Due to pressure from the PCA, no indication of a sexual relationship between Alex and Cassie was in the released film, although they are shown trying to come up with a plausible alibi for arriving late to concert in Rome after going for a drive alone. As reported in Paramount News, background shots in the film were selected from the film records of historic events that preceded World War II, including footage from captured Italian and German newsreels. Paramount News also commented on the use of cork, which had been scarce during the war, to act as noiseless gravel on the driveway set. The Var review of the film states: "The spirit of appeasement, of laissez faire, is strong in the U.S. again. The lessons of the first and second World Wars are apparently forgotten. By recalling the mistakes agreed on, by calling attention...to President Roosevelt's words...[the] film may wake the U.S. up through it's message." The NYT review stated, however, that "no pompous and short-visioned statesmen are likely to be blown over by [the film's] gentle blast." In an article in the SEP entitled "The Role I Liked Best...," Sylvia Sidney states that her character, "Cassie," "in an intensified way, mirrored [her] own feelings about Europe's prewar problems." Sidney's participation in the film made her feel that she was "doing something to bolster the general argument against appeasement."