Question: Dalton Trumbo and David Payne are both which nationality?

Context articles: Trumbo (2007 film)
David Payne (novelist)
Johnny Got His Gun (film)
Trumbo (2015 film)
Peter Askin
Dalton Trumbo
Christopher Trumbo
Executive Action (film)
Eclipse (Trumbo novel)
Tender Comrade

Trumbo is a 2007 American documentary film directed by Peter Askin, produced by Will Battersby, Tory Tunnell, and Alan Klingenstein, and written by Christopher Trumbo.
 It is based on the letters of Trumbo's father, Dalton Trumbo, an Oscar-winning screenwriter who was imprisoned and blacklisted as a member of the Hollywood Ten, ten screenwriters, directors and producers who refused to testify before the House Un-American Activities Committee (HUAC) in 1947 during the committee's investigation of Communist influences in the Hollywood film industry.
David Payne is an American novelist and memoirist.
 He is the author of five novels and a memoir.
 His first novel won the Houghton Mifflin Literary Fellowship Award.
Johnny Got His Gun is a 1971 American drama anti-war film written and directed by Dalton Trumbo and starring Timothy Bottoms, Kathy Fields, Marsha Hunt, Jason Robards, Donald Sutherland and Diane Varsi.
 It was based on the novel of the same name by Trumbo, and features an uncredited writing collaboration by Luis Buñuel.
 The film was released on DVD in the U.S on April 28, 2009 via Shout!
 Factory, with special features.
Trumbo is a 2015 American biographical drama film directed by Jay Roach and written by John McNamara.
 The film stars Bryan Cranston, Diane Lane, Helen Mirren, Louis C.K., Elle Fanning, John Goodman and Michael Stuhlbarg.
 The film follows the life of Hollywood screenwriter Dalton Trumbo and is based on the biography "Dalton Trumbo" by Bruce Alexander Cook.
Peter Askin (Born 1940) is an actor, director, producer and screenwriter best known for directing the 2007 film "Trumbo", a documentary about the Oscar-winning Hollywood screenwriter Dalton Trumbo who was blacklisted for being a member of the Hollywood Ten.
 For the film, he worked closely with Trumbo's son, Christopher Trumbo.
James Dalton Trumbo (December 9, 1905 – September 10, 1976) was an American screenwriter and novelist, who scripted films including "Roman Holiday", "Exodus", "Spartacus", and "Thirty Seconds Over Tokyo".
 One of the Hollywood Ten, he refused to testify before the House Un-American Activities Committee (HUAC) in 1947 during the committee's investigation of Communist influences in the motion picture industry.
 He was subsequently blacklisted by that industry.
 He continued working clandestinely, producing work under other authors' names.
 His uncredited work won two Academy Awards; the one for "Roman Holiday" (1953) was given to a front writer, and the one for "The Brave One" (1956) was awarded to a pseudonym.
 The public crediting of him as the writer of both "Exodus" and "Spartacus" in 1960 marked the end of the Hollywood Blacklist.
 His earlier achievements were eventually credited to him by the Writers Guild, 60 years after the fact.
Christopher Trumbo (September 25, 1940 – January 8, 2011) was an American television writer, screenwriter and playwright.
 Trumbo was considered an expert on the Hollywood blacklist during the McCarthy era.
 His father, screenwriter Dalton Trumbo, was blacklisted by Hollywood for nearly a decade for refusing to testify to Congress, as one of a group known as The Hollywood Ten.
Executive Action is a 1973 conspiracy thriller film about the assassination of U.S. President John F. Kennedy, written by Dalton Trumbo, Mark Lane, and Donald Freed, and directed by David Miller.
 Miller had previously worked with Trumbo on his film "Lonely Are the Brave" (1962).
 It stars Burt Lancaster and Robert Ryan.
Eclipse is Dalton Trumbo's first novel published in 1935.
 The novel is about a town and its people written in the social realist style.
 The town, which Trumbo calls "Shale City," was modeled on Grand Junction, Colorado, where Trumbo lived from 1908 until he left for the University of Colorado in 1924.
 Trumbo's daughter Nikola writes in a foreword to a new edition of Eclipse that the character John Abbott was a substitute for Trumbo's father and "was based on the real-life Grand Junction citizen W.J. Moyer, (who) was also destroyed (as his father had been) by the depression."
 The new edition, published by the Mesa County Public Library Foundation in 2005, includes a list that matches Grand Junction residents to characters in the book and acknowledges that the book's sometimes harsh portrayal of Grand Junction made it controversial in Trumbo's hometown.
Tender Comrade (1943) is a black-and-white film released by RKO Radio Pictures, showing women on the home front living communally while their husbands are away at war.
 The film starred Ginger Rogers, Robert Ryan, Ruth Hussey, and Kim Hunter and was directed by Edward Dmytryk.
 The film was later used by the HUAC as evidence of Dalton Trumbo spreading communist propaganda.
 Trumbo was subsequently blacklisted.
 The film's title comes from a line in Robert Louis Stevenson's poem "My Wife" first published in "Songs of Travel and Other Verses" (1896).