Question: In what war did the country of citizenship of The Spirit House's author lose the most soldiers?

full_context: Document 1: World War II casualties: World War II was the deadliest military conflict in history in absolute terms of total casualties. Over 60 million people were killed, which was about 3% of the 1940 world population (est. 2.3 billion). The tables below give a detailed country - by - country count of human losses. World War II fatality statistics vary, with estimates of total deaths ranging from 50 million to more than 80 million. The higher figure of over 80 million includes deaths from war - related disease and famine. Civilians killed totalled 50 to 55 million, including 19 to 28 million from war - related disease and famine. Military deaths from all causes totalled 21 to 25 million, including deaths in captivity of about 5 million prisoners of war.
Document 2: William Sleator: William Warner Sleator III (February 13, 1945 – August 3, 2011), known as William Sleator, was an American science fiction author who wrote primarily young adult novels but also wrote for younger readers. His books typically deal with adolescents coming across a peculiar phenomenon related to an element of theoretical science, then trying to deal with the situation. The theme of family relationships, especially between siblings, is frequently intertwined with the science fiction plotline.
Document 3: The Boy Who Reversed Himself: The Boy Who Reversed Himself (1986) is a science fiction novel by William Sleator. The novel deals with an exploration into other dimensions, and provides a journey into the world beyond our own.
Document 4: The Spirit House: The Spirit House is a 1993 young adult novel by William Sleator. It was later followed up with the 1997 "Dangerous Wishes".
Document 5: Spires of Spirit: Spires of Spirit, by Gael Baudino, is a collection of six novellas set in the universe of The Strands Series. It was first published in 1997 by Roc Books. The first three stories take place in the time period just prior to "Strands of Starlight" and second three take place in 1990s Denver, USA, about ten years after the flashforwards in "Shroud of Shadow" and before the events depicted in "Strands of Sunlight".
Document 6: The Green Futures of Tycho: The Green Futures of Tycho is a 1981 science fiction novel for young audiences by William Sleator. The book explores the effect of excessive parent expectations on the future of their children.
Document 7: Parasite Pig: Parasite Pig is a young adult science fiction novel written by William Sleator. It is the sequel to the 1984 book "Interstellar Pig".
Document 8: House of Leaves: House of Leaves is the debut novel by American author Mark Z. Danielewski, published in March 2000 by Pantheon Books. A bestseller, it has been translated into a number of languages, and is followed by a companion piece, "The Whalestoe Letters".
Document 9: World War I casualties: The total number of military and civilian casualties in World War I was more than 41 million: there were over 18 million deaths and 23 million wounded, ranking it among the deadliest conflicts in human history.
Document 10: Marco's Millions: Marco's Millions (2001) is a science fiction novel by William Sleator. Marco and his sister Lilly need to deal with the stress that they are the only ones that can save the world. It is a prequel to the main book, "The Boxes".
Document 11: World War II casualties: World War II was the deadliest military conflict in history in absolute terms of total casualties. Over 60 million people were killed, which was about 3% of the 1940 world population (est. 2.3 billion).
Document 12: United States military casualties of war: Rank War Years Deaths Deaths per day U.S. population in first year of war Deaths per population American Civil War 1861 -- 65 750,000 avg. (U.S. / Confederate) 520 31,443,000 2.385% (1860) World War II 1941 -- 45 405,399 297 133,402,000 0.307% (1940) World War I 1917 -- 18 116,516 279 103,268,000 0.110% (1920) Vietnam War 1961 -- 75 58,209 11 179,323,175 0.032% (1970) 5 Korean War 1950 -- 53 54,246 45 151,325,000 0.036% (1950) 6 American Revolutionary War 1775 -- 83 25,000 11 2,500,000 1.00% (1780) 7 War of 1812 1812 -- 15 15,000 15 8,000,000 0.207% (1810) 8 Mexican -- American War 1846 -- 48 13,283 29 21,406,000 0.057% (1850) 9 Iraq War 2003 -- 2011 4,497 294,043,000 0.002% (2010) 10 Philippine -- American War 1899 -- 1902 4,196 3.8 72,129,001 0.006% (1900) 11 Spanish -- American War 1898 2,246 8.9 62,022,250 (1890) 12 War in Afghanistan 2001 - present 2,216 0.36 294,043,000 (2010)
Document 13: Gallows Hill (novel): Gallows Hill (1997) is a supernatural thriller novel for young adults by Lois Duncan. It was her first and only young adult novel written after the death of her daughter. It was written eight years after her previous young adult novel, "Don't Look Behind You". It is about a girl who moves to a small town with a secret.
Document 14: Nosso Lar: Nosso Lar: Life in the Spirit World (Portuguese: "Nosso Lar"), also known as "Astral City", is the best-selling novel by the Brazilian spiritist medium Francisco Cândido Xavier. First published in 1944, the book tells the story of the spirit of André Luiz, a prominent doctor who lived in the city of Rio de Janeiro. After dying, André Luiz encounters neither the Heaven nor the Hell depicted in the teachings he had received during his Catholic upbringing. Rather, he initially has to endure a period in the so-called umbral, a region where less-than-perfect souls face the consequences of their infelicitous actions while alive. After a while, André Luiz is able to perceive the presence of "Clarêncio", a friendly spirit who had been trying to help him all along during his stay in the "umbral". Clarêncio then takes André Luiz to "Nosso Lar", a spirit colony, or astral city, where André becomes acquainted with the intricacies of afterlife and reincarnation.
Document 15: World War I casualties: The total number of military and civilian casualties in World War I was about 40 million: estimates range from 15 to 19 million deaths and about 23 million wounded military personnel, ranking it among the deadliest conflicts in human history.
ground_truth: American Civil War
sub_queries: The Spirit House >> author Answer: William Sleator
William Sleator >> country of citizenship Answer: America
in what war did America lose the most soldiers Answer: American Civil War