Question: Which director is American, Graham Cantwell or Mel Stuart?

Context articles: Mel Stuart
Graham Cantwell
The Callback Queen
Mel Stewart
Running on the Sun: The Badwater 135
The Triangle Factory Fire Scandal
Wattstax
Four Days in November
Willy Wonka &amp; the Chocolate Factory
One Is a Lonely Number

Mel Stuart (born Stuart Solomon; September 2, 1928 – August 9, 2012) was an American film director and producer, who often worked with producer David L. Wolper, whose production firm he worked for 17 years, before going freelance.
Graham Cantwell (born March 25, 1974) is an Irish film and television director.
 He is best known for directing feature film "Anton" which achieved a three-week domestic cinema release and was nominated for three Irish Film and Television Awards in 2009.
 His short film "A Dublin Story" was shortlisted for Academy Award Nomination in 2004 having picked up several film festival awards.
 In 2010 he directed a new television drama "The Guards" for TV3 in Ireland.
 Most recently he directed a romantic comedy set in the film industry in London, "The Callback Queen", which premiered at The Galway Film Fleadh in July 2013 and screened in the U.S. at The Jean Cocteau Cinema, owned and run by George_R.
_R._Martin.
The Callback Queen is a 2013 British romantic comedy independent film by Irish director Graham Cantwell, starring a largely British and Irish cast: Amy-Joyce Hastings, Mark Killeen, Seán T. O'Meallaigh, Ger Ryan, Vicki Michelle and Eoin Macken.
Milton "Mel" Stewart (September 19, 1929 – February 24, 2002) was an American character actor, television director, and musician who appeared in numerous films and television shows from the 1960s to the 1990s.
 He is best known for playing Henry Jefferson on the popular television series "All in the Family" and for playing section chief Billy Melrose on the television series "Scarecrow and Mrs. King".
 Stewart is sometimes credited as Melvin Stewart or Mel Stuart.
Running on the Sun: The Badwater 135 is a 2000 documentary film directed by Mel Stuart.
 The film follows athletes as they run 135 miles in the 1999 Badwater Ultramarathon, starting in California's Death Valley and ending at Whitney Portal, the trailhead to Mount Whitney.
The Triangle Factory Fire Scandal is a 1979 American made-for-television drama film starring David Dukes, Tovah Feldshuh, Lauren Frost, Stacey Nelkin and Ted Wass.
 It was directed by Mel Stuart and premiered on NBC on January 30, 1979.
Wattstax was a benefit concert organized by Stax Records to commemorate the seventh anniversary of the 1965 riots in the African-American community of Watts, Los Angeles.
 The concert took place at the Los Angeles Memorial Coliseum on August 20, 1972.
 The concert's performers included all of Stax's prominent artists at the time.
 The genres of the songs performed included soul, gospel, R&B, blues, funk, and jazz.
 Months after the festival, Stax released a double LP of the concert's highlights titled "Wattstax: The Living Word".
 The concert was filmed by David L. Wolper's film crew and was made into the 1973 film titled, "Wattstax".
 The film was directed by Mel Stuart and nominated for a Golden Globe award for Best Documentary Film in 1974.
Four Days in November is a 1964 American documentary film directed by Mel Stuart about the assassination of John F. Kennedy.
 It was nominated for an Academy Award for Best Documentary Feature.
Willy Wonka & the Chocolate Factory is a 1971 American musical fantasy film directed by Mel Stuart, and starring Gene Wilder as Willy Wonka.
 It is an adaptation of the 1964 novel "Charlie and the Chocolate Factory" by Roald Dahl.
 Dahl was credited with writing the film's screenplay; however, David Seltzer, who went uncredited in the film, was brought in to re-work Dahl's screenplay against his wishes, making major changes to the ending and adding musical numbers.
 These changes and other decisions made by the director led Dahl to disown the film.
One Is a Lonely Number (also known as Two Is a Happy Number) is a 1972 American drama film directed by Mel Stuart and starring Trish Van Devere, Janet Leigh and Melvyn Douglas.
 The screenplay, based upon the short story "The Good Humor Man" by Rebecca Morris, was written by David Seltzer.