The third episode of Netflix’s new historical drama Death by Lightning is titled “Casus Belli,” a Latin phrase that translates to “an occasion for war” or “an act that justifies a conflict.” The title perfectly captures the episode’s plot, where political tensions within the White House reach a boiling point, and a delusional office seeker decides to take drastic action. The series, which premiered on November 6, 2025, stars Michael Shannon as President James Garfield and Matthew Macfadyen as his assassin, Charles Guiteau.
The Literal Meaning of Casus Belli
Casus Belli is a Latin term used to describe an event or action that is used to justify a war. As defined by Merriam-Webster, it is “an event or action that justifies or allegedly justifies a war or conflict.” In the context of Death by Lightning, the title signals a major turning point in the series where multiple characters decide they have a reason to go to war against President Garfield.
How ‘Casus Belli’ Drives the Plot in Episode 3
In “Casus Belli,” President Garfield makes a firm stand against the corrupt political machine that helped him get elected. With the help of James Blaine, played by Bradley Whitford, Garfield tries to end corruption by appointing new senators, rejecting the corrupt candidates suggested by powerful New York Senator Roscoe Conkling.
This move is seen as a direct act of defiance. Roscoe Conkling and Vice President Chester A. Arthur, feeling betrayed, begin plotting to overthrow Garfield. They kidnap the senators Garfield appointed and threaten them, forcing them to step down. This political betrayal is one of the major “causes for war” in the episode.
At the same time, Charles Guiteau, a delusional admirer of Garfield, reaches his breaking point. After numerous failed attempts to secure a government job, he becomes convinced the president is not the man he thought he was. The episode ends with Guiteau buying a gun, setting the stage for his tragic and history-changing decision.
The Real Historical Context Behind the Show
Death by Lightning is based on the true story of James Garfield’s presidency and assassination, as detailed in Candice Millard’s book, Destiny of the Republic. Garfield was president for only 120 days before he was shot by Charles Guiteau, a disgruntled office seeker. He survived for another 80 days before dying from his wounds.
The series creator, Mike Makowsky, was inspired by the parallel stories of these two men. He compared Charles Guiteau to Robert De Niro’s character in the film The King of Comedy, a man so desperate for recognition that he becomes dangerously obsessed. This obsession is shown throughout the series as Guiteau constantly tries and fails to get a meeting with the president, ultimately leading him to violence.
โHe becomes obsessed with him,โ Matthew Macfadyen, who plays Guiteau, said of his character’s fixation on Garfield. โAll his eggs go into the Garfield basket, and then, of course, he feels very let down and betrayed.โ
Fan Reactions and Critical Praise
The series has been met with widespread critical acclaim, holding a 90% rating on Rotten Tomatoes. Critics have particularly praised the performances of Michael Shannon and Matthew Macfadyen. Many viewers have expressed that they were previously unaware of this fascinating piece of American history and found the show both educational and gripping.
One fan review on IMDb noted, “I never knew this part of history. This series is not to be missed!โฆ Garfield embodies what we should look for and expect from our country’s leader.” Another wrote, “The acting is superbโฆ Matthew Macfadyen nails the role of Charles Guiteau, one of the creepiest villains we’ve seen recently.”
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