American War is a speculative fiction novel published in 2017 by the Canadian-Egyptian author Omar El Akkad. Set in a dystopian near-future in which climate change has displaced millions, the book details a Second American Civil War fought between the federal government and the Southern United States over the use of fossil fuels. Prior to writing American War, El Akkad reported from conflict zones in Afghanistan and Egypt as a journalist for The Globe and Mail. A finalist for the Arthur C. Clarke award, American War also appears on the BBC's list of "100 Novels that Shaped our World." El Akkad is also the author of What Strange Paradise, published in 2021.

This study guide refers to the 2017 edition published by Alfred A. Knopf.

In a prologue, the narrator—Simon Chestnut’s son, Benjamin, named after Simon’s father—explains the massive social and political changes of the mid-to-late 21st century. Due to climate change and rising sea levels, much of the American East Coast is underwater or uninhabitable. In response, lawmakers in the new federal capital of Columbus, Ohio pass the Sustainable Future Act, prohibiting the use of fossil fuels nationwide. Perceiving their industries and traditions to be under attack, five Southern states secede from the United States. The earliest state to revolt, South Carolina, is now completely walled-off and quarantined after the federal government unleashes what was designed to be a temporary virus but which causes everyone in its path to suffer permanent zombie-like symptoms. As Texas fights a two-fronted war against Mexico and the North, Mississippi, Alabama, and Georgia make up the Free Southern State, a belligerent coalition that fights the federal government in a Second American Civil War lasting from 2074 to 2095.

After the prologue, the novel is divided into four parts. Part 1 is set in 2075, a year after the outbreak of the war. The Chestnut family consists of Martina and Benjamin, and their three children: nine-year-old Simon and six-year-old fraternal twins, Dana and Sarat. Because they live in the "purple state" of Louisiana, Benjamin requires a work permit to relocate his family to the North, where it is safer and there are more jobs. However, while applying for a permit, Benjamin dies in a Rebel "homicide bomber" attack on Baton Rouge's federal building. Terrified that the fighting will reach her doorstep, Martina relocates her family to the Camp Patience refugee camp in Iuka, Mississippi, just South of the border to the Northern-aligned state of Tennessee.

Part 2 is set six years later in 2081. As the war continues, the Chestnuts fall into a routine at Camp Patience. One day, 12-year-old Sarat meets a man named Albert Gaines who teaches her about history, music, and most of all, Northern atrocities. He also introduces her to Joe, a citizen of the Bouazizi Union. The Bouazizi Union is a coalition of democratic states in North Africa and the Middle East. Throughout the war, Bouazizi offers military and humanitarian aid to the Free Southern State to prolong the conflict and further destabilize the United States. One night, Northern militiamen storm Camp Patience, slaughtering everyone in their path. Martina is murdered, while Dana and Sarat only survive by hiding in Gaines' locked office. Simon suffers a gunshot wound to the head but miraculously survives, albeit with significant brain damage.

In Part 3, the year is 2086. Sarat, Dana, and Simon live in a Charity House in Lincolnton, Georgia, provided to them by the federal government as victims of the Camp Patience massacre. Sarat, now 17, trains in the forest with Gaines, learning to shoot. Simon has shown significant improvement in his mental faculties, learning to feed and clothe himself, but he can only communicate with others at a child's level. Sarat's first major insurgency mission is to assassinate the North's top military commander, General Joseph Weiland. She successfully carries out the assassination without being identified. A few months later, Dana is killed in a drone strike. A week later, federal authorities storm the Chestnut homestead and detain Sarat at the Sugarloaf Detention Center. Unaware of her connection to General Weiland's assassination, interrogators attempt to draw out confessions from Sarat of crimes she did not commit. Over the next three years, Sarat's captors inflict various tortures on her to get her to talk, including making her stand with her wrists chained to her ankles under searing hot floodlights for 20 straight days.

In her third year, the meanest of the Sugarloaf guards, Bud Baker, brings Sarat to an unfamiliar room where interrogators waterboard her. The experience is more excruciating than any of her previous tortures, and Sarat quickly confesses to all the crimes of which she is accused, even though she did not commit any of them. For the next four years, she survives in Sugarloaf largely unmolested but a broken woman. Finally, a woman arrives to inform Sarat that the war is over and that the intelligence implicating her in various crimes is not credible. Within days, Sarat is released.

In Part 4, the year is 2095. Sarat moves in with Simon, whose mental faculties have improved dramatically. With his wife and former caretaker Karina, Simon has a six-year-old son named Benjamin. At first, Sarat is intensely withdrawn but slowly she begins to bond with her nephew, Benjamin.

One day, Joe arrives at the Chestnut home. He tells Sarat that Gaines sold her out after authorities threatened his wife and daughter. Further, Joe tells Sarat he's obtained a virus that could wipe out millions in the North. Full of rage over everything's she lost and been through, Sarat agrees to unleash the virus in Columbus on Reunification Day that July. Before doing so, she enlists two of her old Rebel comrades to relocate Benjamin to New Anchorage, Alaska, a neutral state far away from the coming devastation. The virus kills 110 million people in the North and South alike, fulfilling the Bouazizi Union's goal of destabilizing the United States.

Benjamin grows up to be a history scholar specializing in the Second American Civil War. One day, he figures out that the numbers on a goodbye letter from Sarat indicate geographic coordinates. There, he finds Sarat's diary, detailing her life story and all her crimes, including the virus attack. Furious that Sarat killed millions including his parents, Benjamin burns the pages. It is only late in his life, as he succumbs to cancer, that Benjamin reproduces Sarat's story in this book.