Mighty Derringer: The Failed Fallout Plots of Indianapolis

By Roy Castellano · September 9, 2026

Washington's planners executed a nuclear simulation in Indianapolis but failed to prepare for the most volatile element: the human fallout.

The first sign of a nuclear strike in the Crossroads of America would not be the flash, but the silence of a government that has forgotten how to speak to its own people. In the simulated aftermath of a detonation in Indianapolis, the technical machinery of the state functioned with precision, but the human element—the very people the state is meant to protect—was left in a vacuum of incomprehensible data. This is the cost of planning for a catastrophe while ignoring the people living through it.

What survives of this specific moment in contingency planning is an archival description of a memo, not the memo's own pages. The description identifies a document titled "First Impressions: Mighty Derringer: Consequence Phase," sent from Richard F. Smale of HSE to Carl Henry and Bill Chambers. It captures a critique that is as much about the failure of political communication as it is about the science of radiation.

The Technical Success of a Nightmare

Richard F. Smale, an expert with HSE—the organization responsible for the technical oversight of this simulation—noted that the exercise showed "great things" in its technical organization. Smale, an American mathematician known for his research into the complex dynamics of systems, brought a rigorous eye to the mechanics of the disaster. He saw a simulation that could model the physics of a blast, the movement of debris, and the technical logistics of a state in crisis. But Smale’s assessment was not a clean bill of health.

He pointed to a critical deficit in the "consequence phase," the period immediately following the detonation. The simulation failed to provide information that was accessible to a non-technical audience. While the engineers and the planners could read the charts, the citizens of Indianapolis—a major North American transportation hub and the densely populated capital of Indiana—were left with nothing but the debris. Smale further noted a lack of time to "develop good fallout plots," the essential maps that tell a population where it is safe to stand and where the wind is carrying death.

Document imagery from nsarchive.gwu.edu From the files: nsarchive.gwu.edu

A Language for the Living

The recipients of Smale's critique, Carl Henry and Bill Chambers, represent the high-level intelligence and policy profiles that typically receive such "first impressions." They were the ones for whom the technicalities mattered less than the implications for command and control. When a mathematician of Smale's caliber warns that the information provided to the public is inaccessible, he is not merely complaining about jargon. He is warning that the state is preparing to operate in a world where it has lost the ability to lead.

The public record shows that during this era, the focus of such exercises was often the preservation of the state’s core functions. However, Smale’s memo highlights a disconnect. The technical organization of Mighty Derringer was a triumph of engineering, but its failure to produce usable fallout plots suggests a government more interested in the movement of its own assets than the survival of its constituency. If the planners cannot tell the people of Indianapolis where the radiation is moving, they are not planning a rescue; they are planning an abandonment.

Mighty Derringer and the Command Structure

There is a cold irony in the codename. "Mighty Derringer" suggests a small, perhaps concealable, instrument of force—a tool used for quick, decisive action. But the scale of the simulation, a nuclear event in the heart of the Midwest, is anything but small. The connection between the technical precision Smale admired and the communication failures he decried points to a deeper, more unsettling priority. The simulation was successful at modeling the blast, but it was a failure at modeling the response of a living, breathing, and terrified populace.

If the shape of this file is what it appears to be, the technical successes noted by Smale were a mask. The focus on the "consequence phase" was not merely about radiological containment. The pattern suggests that Mighty Derringer was an assessment of the continuity of government—a test to see if the political command structures could remain resilient even when the social fabric of a major American city was incinerated. The inability to communicate with a non-technical audience wasn't a logistical oversight; it was a symptom of a system designed to operate above the level of the citizenry.

The Silence of the Fallout

The desk's reading is that Mighty Derringer was a social control simulation disguised as a radiological drill. The emphasis on the failure to reach a "non-technical audience" reveals the true fear of the planners: not the radiation itself, but the unpredictable reaction of a public that does not understand the government's instructions. If the population cannot be guided by clear, accessible information, they cannot be managed. The lack of "good fallout plots" meant that the state had no way to dictate the movement of the people, and in a simulation of domestic catastrophe, unmanaged movement is synonymous with chaos.

If this file is shaped the way it looks, the suppressed information within the full record—the details the description leaves out—likely concerns the intended threat profile. We do not know if Mighty Derringer modeled an adversary strike or a catastrophic domestic accident, but the distinction is vital. An adversary strike demands a mobilization of the public; a domestic accident demands their containment. The heavy emphasis on managing the "consequence phase" for high-level recipients suggests the latter was the true objective.

A full release of these files would likely show that the state was not practicing how to save Indianapolis, but how to survive the political fallout of its destruction. The pattern suggests that the real exercise was about the resilience of power, testing how much of the country could be lost before the command structure itself felt the heat. The people of Indianapolis were not the subjects of the drill; they were merely the terrain upon which the state practiced its own survival.

Mighty Derringer: The Failed Fallout Plots of Indianapolis

The Technical Success of a Nightmare

A Language for the Living

Mighty Derringer and the Command Structure

The Silence of the Fallout

Sources