while dalton trumbo political and professional travail certainly affect his outlook and i believe he look more to conventional history in script the bos . trumbo certainly use the corrupt democratic political machine of tom pendergast a the template for his script . small wonder . the pendergast machine be one of the most enduring municipal fief of the mid twentieth century . the crook that payne be force to make deal with in the bos appear to be base on the real life overlord of kansas city prohibition era crime and johnny lazia . the gunfight sequence at the train station be directly draw from the famous kansa city massacre of 1933 when pretty boy floyd and adam richetti and verne miller mow down several f. b. i. agent and also kill the crook they be try to rescue and frank jelly nash . another interest parallel between the film and actual history be that harry s. truman be sponsor by tom pendergast and manage to keep himself personally clean and advance his political career while remain loyal to the machine . truman be portray down to his glass in the bos by joe flynn and subsequently know to many a captain binghamton in mchale navy . one little known historical fact that be leave out be that truman first official act upon become president after f. d. r. die in 1945 be to fire the u. s. attorney for missouri who successfully prosecute tom pendergast for tax evasion and send him to prison in 1939. truman be loyal to pendergast to the very end .