While Dalton Trumbo's political and professional travails certainly affected his outlook, I believe he looked more to conventional history in scripting "The Boss".<br /><br />Trumbo certainly used the corrupt Democratic political machine of Tom Pendergast as the template for his script. Small wonder. The Pendergast machine was one of the most enduring municipal fiefs of the mid-twentieth century.<br /><br />The crook that Payne is forced to make deals with in "The Boss" appears to be based on the real-life overlord of Kansas City prohibition-era crime, Johnny Lazia. The gunfight sequence at the train station is directly drawn from the famous 'Kansas City Massacre' of 1933 when 'Pretty Boy' Floyd, Adam Richetti and Verne Miller mowed down several F.B.I. agents and also killed the crook they were trying to rescue, Frank 'Jelly' Nash.<br /><br />Another interesting parallel between the film and actual history is that Harry S. Truman was sponsored by Tom Pendergast and managed to keep himself personally clean and advance his political career while remaining loyal to the Machine. Truman is portrayed down to his glasses in "The Boss" by Joe Flynn, subsequently known to many as "Captain Binghamton in "McHale's Navy".<br /><br />One little known historical fact that was left out is that Truman's first official act upon becoming President after F.D.R. died in 1945 was to fire the U.S. Attorney for Missouri who successfully prosecuted Tom Pendergast for tax evasion and sent him to prison in 1939.<br /><br />Truman was loyal to Pendergast to the very end.