powered by AFI
Pre-production titles of the film included The River Is Blue, Castles in Spain and The Loves of Jeanne Ney. Other titles by which the film was known during production, but prior to release, included The Rising Tide and The Adventuress. According to news items in Hollywood Reporter in late February and early March 1937, the production was scheduled to begin filming as The River Is Blue in late Feb, under Lewis Milestone's direction, based on a script by noted playwright Clifford Odets. The items mentioned that a male lead had not been cast opposite Madeleine Carroll, but that Milestone was testing actors Willy Costello, Alan Marshall and Elia Kazan. Finally, on 4 Mar, a news item announced that the production was being postponed and the sets were to be struck. Filming under William Dieterle's direction did not begin until almost a year later, on February 16, 1938, with Henry Fonda as the male lead. All sources after 1937 only credit John Howard Lawson with original screenplay, and it appears that Odets' script was abandoned before the 1938 production began.
Portions of the film were shot on location in Brent's Craig, CA. Just prior to the release of the film, NBC radio broadcast a program featuring the musical score, accompanied by a voice over narration by Fonda and Carroll providing explanatory background on the film. Although the setting of the film is established as Spain in the spring of 1936 by a title card appearing on screen after the opening credits, no specific mention is made in the film of the Spanish Civil War, or of the two opposing sides, the Loyalists and the Fascists. The "enemy" to the character Marco's people is never named and the action and dialogue of the film vaguely infer a foreign invasion rather than a civil war. At the end of the film, Fonda delivers his last few lines, including the question "Where's the conscience of the world?" directly to the audience. The review in Variety criticized Lawson for not making his script more explicit, but according to contemporary news items and information contained in the file on the film in the MPAA/PCA Collection at the AMPAS Library, the Hays Office refused to allow references to the actual combatants in Lawson's original script, entitled Castles in Spain, to remain in the released film.
Other information in the file and contemporary news items document protests throughout the United States against the film. Various groups, including the Roman Catholic men's organization, The Knights of Columbus, accused the filmmakers of leftist sympathies. The Knights of Columbus Bulletin of 1938 said that the "director has ambition to glorify Karl Marx." In Boston, groups of protesting Catholics sought to have the film banned, but the mayor refused to comply and the film remained on exhibition. Pickets also protested the film at its Radio City Music Hall showing in New York. Editorials in several newspapers and magazines argued the political merits of the film. Box Office condemned the Knights of Columbus campaign to have the film banned and in the publication Hollywood Now: A Journal in Defense of American Democracy, director John Ford praised the film saying, "I am not going to speak as a Catholic, nor as a member of the Knights of Columbus for twenty years, nor in the name of Francis Ford, my nephew in the Abraham Lincoln Battalion in Spain, nor as a member of the Screen Directors Guild, but as a private citizen...Great entertainment...great human document." A decade after Blockade was released, screenwriter Lawson was sentenced to a year in prison for refusing to testify before the House Un-American Activities Committee. He was one of the "Hollywood Ten," a group of filmmakers who refused to reveal information about alleged Communist affiliations of themselves or others.
Blockade received Academy Award nominations in the Music (Original Score) and Writing (Original Story) categories.