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The Scientist Turned Spy: André Michaux, Thomas Jefferson, and the Conspiracy of 1793
The incredible story of an explorer caught up in international intrigue at the dawn of US history
André Michaux was the most famous scientific explorer of North America before Lewis and Clark. His work took him from the Bahamas to Hudson Bay, and it is likely that no contemporary of his had seen as much of the continent. But there is more to his story.
During his decade-long American sojourn, Michaux found himself thrust into the middle of a vast international conspiracy. In 1793, the revolutionary French government conscripted him into its service as a secret agent and tasked him with organizing American frontiersmen to attack Spanish-controlled New Orleans, seize control of Louisiana, and establish an independent republic in the American West. New evidence also strongly implicates Thomas Jefferson in this plot. Drawing on sources buried in the vault of the American Philosophical Society, Patrick Spero offers a bona fide page-turner that sheds new light on an incipient American political climate that fostered reckless diplomatic ventures under the guise of scientific exploration, revealing the air of uncertainty and opportunity that pervaded the early republic.
André Michaux was the most famous scientific explorer of North America before Lewis and Clark. His work took him from the Bahamas to Hudson Bay, and it is likely that no contemporary of his had seen as much of the continent. But there is more to his story.
During his decade-long American sojourn, Michaux found himself thrust into the middle of a vast international conspiracy. In 1793, the revolutionary French government conscripted him into its service as a secret agent and tasked him with organizing American frontiersmen to attack Spanish-controlled New Orleans, seize control of Louisiana, and establish an independent republic in the American West. New evidence also strongly implicates Thomas Jefferson in this plot. Drawing on sources buried in the vault of the American Philosophical Society, Patrick Spero offers a bona fide page-turner that sheds new light on an incipient American political climate that fostered reckless diplomatic ventures under the guise of scientific exploration, revealing the air of uncertainty and opportunity that pervaded the early republic.
352 pages, Hardcover
First published September 17, 2024
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Displaying 1 - 5 of 5 reviews
May 19, 2024
André Michaux, a gifted botanist, was slated to be the original Lewis and Clark, cutting the first path to the Pacific accompanied by Native guides. Then the French Revolution happened, the busybody Citizen Genêt joined us, plans changed. The new plan was for Michaux to be the vanguard of Kentuckians' invasion of Spanish Louisiana, to be followed by the establishment a glorious republic à la France (and the United States).
Patrick Spero's The Scientist Turned Spy explores this little-known chapter of American history in exhaustive detail, delving, for instance, into the nuances of the American Philosophical Society, which planned to sponsor the purely botanistic journey that Michaux never took. Though it sometimes seemed overlong, the great merit in this book is Spero's expert portrayal of the tension between the Jeffersonian and Washington/Hamiltonian visions for governance of the new United States, culminating in Washington fighting with himself over whether to use federal troops against American citizens of the west, who were disillusioned with what they saw as the new national government's favoritism toward the eastern states. You'd forgive General Washington for collecting most of his famous silvery hair during this nail-biter.
There is too a fascinating review of the ample evidence to support, not only the idea that Jefferson was in thrall to the French Revolution, but that Jefferson had full knowledge of Citizen Genêt's plot to kick Spain out of Louisiana, which risked treacherous destabilization on the continent. I highly recommend The Scientist Turned Spy to those interested in early American history.
Patrick Spero's The Scientist Turned Spy explores this little-known chapter of American history in exhaustive detail, delving, for instance, into the nuances of the American Philosophical Society, which planned to sponsor the purely botanistic journey that Michaux never took. Though it sometimes seemed overlong, the great merit in this book is Spero's expert portrayal of the tension between the Jeffersonian and Washington/Hamiltonian visions for governance of the new United States, culminating in Washington fighting with himself over whether to use federal troops against American citizens of the west, who were disillusioned with what they saw as the new national government's favoritism toward the eastern states. You'd forgive General Washington for collecting most of his famous silvery hair during this nail-biter.
There is too a fascinating review of the ample evidence to support, not only the idea that Jefferson was in thrall to the French Revolution, but that Jefferson had full knowledge of Citizen Genêt's plot to kick Spain out of Louisiana, which risked treacherous destabilization on the continent. I highly recommend The Scientist Turned Spy to those interested in early American history.
November 8, 2025
* It's really a 4.5* I had the excellent opportunity to see Spero speak about this book last year, and I finally got the chance to dive into it. It did not disappoint.
As a historian, I have read my fair share of dry, factual, lecture-based books, and it takes patience and time to digest them. Spero is a natural at making complex and often convoluted historical periods easily digestible for the average reader and historian alike. It is a story of an otherwise forgotten botanist on a quest for new knowledge, traveling from France to America on the cusp of the French Revolution. He leaves one complicated environment and enters another. André Michaux, a botanist who would rather be left to his discoveries, is at the financial mercy of a king about to be beheaded, then to multiple fragile governments, then to American scientists, and finally to a scheming, sometimes loud-mouthed ambassador named Edmond Genet. In the pursuit of seeking new knowledge, Michaux is stuck between the scheming Genet, radical George Rogers Clark, who thinks America has turned its back on the West, the Spanish, the French, and Secretary of State Thomas Jefferson, who believes the knowledge found out West might just be worth the dabble in treachery. With his reliance on the financial support of others, his unyielding need to discover new botanical specimens, and a dependence on enslaved people working on his behalf, as well as the help of indigenous translators and guides, and weather than doesn't quite work in his favor, and of course the politics of everyone around him, the reader will follow a story fit for an HBO Drama miniseries.
As a historian, I have read my fair share of dry, factual, lecture-based books, and it takes patience and time to digest them. Spero is a natural at making complex and often convoluted historical periods easily digestible for the average reader and historian alike. It is a story of an otherwise forgotten botanist on a quest for new knowledge, traveling from France to America on the cusp of the French Revolution. He leaves one complicated environment and enters another. André Michaux, a botanist who would rather be left to his discoveries, is at the financial mercy of a king about to be beheaded, then to multiple fragile governments, then to American scientists, and finally to a scheming, sometimes loud-mouthed ambassador named Edmond Genet. In the pursuit of seeking new knowledge, Michaux is stuck between the scheming Genet, radical George Rogers Clark, who thinks America has turned its back on the West, the Spanish, the French, and Secretary of State Thomas Jefferson, who believes the knowledge found out West might just be worth the dabble in treachery. With his reliance on the financial support of others, his unyielding need to discover new botanical specimens, and a dependence on enslaved people working on his behalf, as well as the help of indigenous translators and guides, and weather than doesn't quite work in his favor, and of course the politics of everyone around him, the reader will follow a story fit for an HBO Drama miniseries.
December 18, 2024
This is a fascinating non-fiction history book by Patrick Spero, “The Scientist Turned Spy: André Michaux, Thomas Jefferson, and the Conspiracy of 1793.” I highly recommend it for anyone who is interested in historical botany AND the history of our nation’s political interest in scientific progress (and actions to promote science research taken by the American Founding Fathers). I don’t read much American history so I appreciated how well this book clearly walked me through geographic regions and events in our history at a time when Kentucky was the civilized west in need of opening trade routes via New Orleans.
March 18, 2026
Patrick Spero’s The Scientist Turned Spy tells the story of French botanist André Michaux and his involvement with a short-lived conspiracy to incite an invasion of Spanish Louisiana from Kentucky, a plot that involved numerous notable Americans to one extent or another, including future U.S. President and then–Secretary of State Thomas Jefferson. Along the way, Spero examines the currents of 18th-century science, society, and politics as they intersect with Michaux’s journey, and explores the impact of the titular Conspiracy of 1793 on the fledging United States. While not a traditional biography, The Scientist Turned Spy also highlights the significant scientific accomplishments of Michaux and suggests that he deserves more recognition than he commonly receives.
The Scientist Turned Spy is divided into four parts. Part One provides a biography on André Michaux prior to 1792, when he associated with the American Philosophical Society (APS) and began planning an expedition into the American West. It is perhaps unfair to complain that this section is overly short; as noted previously, The Scientist Turned Spy is not intended as a complete biography of Michaux. Nonetheless, there is much in this section that leaves the reader wanting more. Only a few pages are dedicated to Michaux’s trip to Persia, and tantalizing statements like “he was accosted by robbers, caught in hazardous sandstorms, and faced off with several dangerous and deadly animals” (Spero 26) are left unelaborated upon. A single paragraph is dedicated to Michaux’s marriage and the tragic early death of his wife, a situation which, if explored further, might have allowed the reader to connect more deeply with Michaux as a character. Spero often notes that Michaux’s writings contain very little personality, and these instances might have served to remedy that issue, at least in part.
Where Part One, and the book as a whole, excels is in portraying the times, more so than the life, of Michaux. There is much useful information on the state of science—or “natural history” and “natural philosophy,” as it was then called—during the period. Spero helpfully elucidates how the scientific endeavor was simultaneously a globalist enterprise driven by an Enlightenment impulse to increase the sum of human knowledge, and a nationalistic one driven by a desire to win scientific glory for one’s motherland and to transplant valuable natural resources to the home country. Part Two expands on this, focusing on specifically on science in the American context. It explores Michaux’s proposed expedition to the American West sponsored by the APS and the various backers the expedition attracted, notably Thomas Jefferson. Among Jefferson’s many motives was one typical of the nationalist influence on science: to disprove George-Louis Leclerc’s thesis that “the American environment produced smaller, weaker plants and animals” (Spero 82).
Part Three recounts how Edmond Genet’s arrival in the U.S. changed Michaux’s expedition from a purely scientific excursion to a political one. It details how Michaux was tasked with arranging for an invasion of Spanish Louisiana, to be led by George Rogers Clark and manned by frontier Kentuckians. Spero does an excellent job of telling the whole sordid story of the Genet Affair and the divisions it revealed and exacerbated in American politics. He also deftly traces the steps of Genet and Michaux as they carried out their plan, using primary source documentation to figure out who knew about the plot and when they knew it. He does not shy away from drawing the uncomfortable conclusion that Jefferson, according to the personal accounts of both Jefferson and Genet, was aware and even supportive of the intrigue, while also presenting the “concatenation of events that … influenced his thinking” (Spero 165).
As Spero relates, the plan for invasion ultimately came to nothing. Part Four wraps things up by providing a brief account of the rest of Michaux’s life and then considering the legacies of the other main characters in the story. Especially noteworthy is Spero’s argument that the militant Kentuckians who would have composed the invasion army “achieved their immediate aim” (Spero 256) of opening the Mississippi River by pressuring the U.S. and Spanish governments to reach a settlement to forestall the invasion—a fact that inspired similar radical movements in the future. This elevates the Conspiracy of 1793 from a mere piece of historical trivia to a significant moment in early U.S. history.
The Scientist Turned Spy combines breezy, readable prose with deep research to illuminate a largely forgotten French scientist and his involvement in a largely forgotten moment in American history. It excels at demonstrating how individual people and scenarios reflect broader societal trends throughout history. Accessible to layfolk and scholars alike, it should spark interest in its topic and encourage readers to consider the relationship between historical figures and the complex atmosphere in which they lived.
________________________
Written for my Early American Republic class at Randolph-Macon College.
EDIT: I received a B-. My professor pointed out that I summarized too much, without providing critical comment (positive or negative). He also pointed out that I did not address Spero's thesis or arguments. This is, in part, because I did not really feel like Spero had a proper thesis that he was advancing through arguments - that it was mainly just telling a story, and any conclusions to be drawn were secondary to the story itself. I could've spun something, though, and I know for a fact that he would have liked it based off of how he responded to my comments in our class discussion on the book. Oh well. Live and learn.
The Scientist Turned Spy is divided into four parts. Part One provides a biography on André Michaux prior to 1792, when he associated with the American Philosophical Society (APS) and began planning an expedition into the American West. It is perhaps unfair to complain that this section is overly short; as noted previously, The Scientist Turned Spy is not intended as a complete biography of Michaux. Nonetheless, there is much in this section that leaves the reader wanting more. Only a few pages are dedicated to Michaux’s trip to Persia, and tantalizing statements like “he was accosted by robbers, caught in hazardous sandstorms, and faced off with several dangerous and deadly animals” (Spero 26) are left unelaborated upon. A single paragraph is dedicated to Michaux’s marriage and the tragic early death of his wife, a situation which, if explored further, might have allowed the reader to connect more deeply with Michaux as a character. Spero often notes that Michaux’s writings contain very little personality, and these instances might have served to remedy that issue, at least in part.
Where Part One, and the book as a whole, excels is in portraying the times, more so than the life, of Michaux. There is much useful information on the state of science—or “natural history” and “natural philosophy,” as it was then called—during the period. Spero helpfully elucidates how the scientific endeavor was simultaneously a globalist enterprise driven by an Enlightenment impulse to increase the sum of human knowledge, and a nationalistic one driven by a desire to win scientific glory for one’s motherland and to transplant valuable natural resources to the home country. Part Two expands on this, focusing on specifically on science in the American context. It explores Michaux’s proposed expedition to the American West sponsored by the APS and the various backers the expedition attracted, notably Thomas Jefferson. Among Jefferson’s many motives was one typical of the nationalist influence on science: to disprove George-Louis Leclerc’s thesis that “the American environment produced smaller, weaker plants and animals” (Spero 82).
Part Three recounts how Edmond Genet’s arrival in the U.S. changed Michaux’s expedition from a purely scientific excursion to a political one. It details how Michaux was tasked with arranging for an invasion of Spanish Louisiana, to be led by George Rogers Clark and manned by frontier Kentuckians. Spero does an excellent job of telling the whole sordid story of the Genet Affair and the divisions it revealed and exacerbated in American politics. He also deftly traces the steps of Genet and Michaux as they carried out their plan, using primary source documentation to figure out who knew about the plot and when they knew it. He does not shy away from drawing the uncomfortable conclusion that Jefferson, according to the personal accounts of both Jefferson and Genet, was aware and even supportive of the intrigue, while also presenting the “concatenation of events that … influenced his thinking” (Spero 165).
As Spero relates, the plan for invasion ultimately came to nothing. Part Four wraps things up by providing a brief account of the rest of Michaux’s life and then considering the legacies of the other main characters in the story. Especially noteworthy is Spero’s argument that the militant Kentuckians who would have composed the invasion army “achieved their immediate aim” (Spero 256) of opening the Mississippi River by pressuring the U.S. and Spanish governments to reach a settlement to forestall the invasion—a fact that inspired similar radical movements in the future. This elevates the Conspiracy of 1793 from a mere piece of historical trivia to a significant moment in early U.S. history.
The Scientist Turned Spy combines breezy, readable prose with deep research to illuminate a largely forgotten French scientist and his involvement in a largely forgotten moment in American history. It excels at demonstrating how individual people and scenarios reflect broader societal trends throughout history. Accessible to layfolk and scholars alike, it should spark interest in its topic and encourage readers to consider the relationship between historical figures and the complex atmosphere in which they lived.
________________________
Written for my Early American Republic class at Randolph-Macon College.
EDIT: I received a B-. My professor pointed out that I summarized too much, without providing critical comment (positive or negative). He also pointed out that I did not address Spero's thesis or arguments. This is, in part, because I did not really feel like Spero had a proper thesis that he was advancing through arguments - that it was mainly just telling a story, and any conclusions to be drawn were secondary to the story itself. I could've spun something, though, and I know for a fact that he would have liked it based off of how he responded to my comments in our class discussion on the book. Oh well. Live and learn.
March 8, 2026
Patrick Spero's "Scientist Turned Spy: And the Conspiracy of 1793" is a book of multiple fascinations. Primarily, it is a solid biography of Andre Michaux, a dedicated French botanist who traveled the world in pursuit of scientific knowledge of plants and animals. His travels included years spent in the newly established United States of America. His work brought him into the sphere of America's early scientific community and political leaders. These included Benjamin Franklin, fellow botanists such as John Bartram, many members of the American Philosophical Society, George Washington and Thomas Jefferson. These contacts would eventually bring Michaux into a plot that could have been dangerous for the newly formed nation.
He came to the United States in the employ of French king, Louis XVI who wanted new species of trees to restore the depleted French forests, a matter of "national security," Spero writes. The French Revolution left Michaux uncertain of his job, but the new government continued to support him financially. This support allowed him to travel extensively, including to the Hudson Bay, and to establish nurseries in New Jersey and South Carolina. From his field trips and these nurseries he was able to send a continuing array of new plants of ornamental and possibly economic importance back to France.
Jefferson and the American Philosophical Society were impressed with Michaux. They solicited funds to pay for an expedition he would lead to the American West to find the quickest route to the Pacific Ocean while also investigating the plant, animal, and other resources he encountered. The funds were raised, but Michaux eventually declined when the detailed interests of the two parties conflicted. That expedition would await the journey of Lewis and Clark under President Jefferson.
Edmond Genet, the newly arrived French ambassador to the Capital in Philadelphia, offered Michaux another opportunity of exploring westward. Here began Michaux's role as under cover agent. The vast expanse of the North American continent west of the Mississippi was still in the hands of the indigenous Tribes. European interests, largely French, British, and Spanish, had holdings, and designs, on this territory. The Spanish, for instance, held the city of New Orleans. This gave them control of shipping from the outlet of the Great River, something that irritated the American settlers who wished to use the port to ship their goods abroad without paying fees to a foreign nation.
The French, who were at war with Spain in Europe, wanted to have American settlers along the Ohio and Mississippi Rivers strike and dislodge the Spanish from New Orleans. Ambassador Genet engaged Michaux to head to Kentucky to help organize the locals to play this insurgent role. He would use his scientific investigations as cover for his visiting the area.
Author Spero reveals the role of many national and local government officials, including Secretary of State Jefferson, in abetting this plan. The United States had peaceful relations with Spain at this time, so participating in the French planned armed attack would violate American policy. The author notes that Jefferson's duplicitous behavior in this plot has been called traitorous by some earlier historians. He also uses the incident to identify the origin of political parties in the United States.
The subsequent varying fates of the many participants makes for interesting reading . Overall, an exciting journey through America's early history.
He came to the United States in the employ of French king, Louis XVI who wanted new species of trees to restore the depleted French forests, a matter of "national security," Spero writes. The French Revolution left Michaux uncertain of his job, but the new government continued to support him financially. This support allowed him to travel extensively, including to the Hudson Bay, and to establish nurseries in New Jersey and South Carolina. From his field trips and these nurseries he was able to send a continuing array of new plants of ornamental and possibly economic importance back to France.
Jefferson and the American Philosophical Society were impressed with Michaux. They solicited funds to pay for an expedition he would lead to the American West to find the quickest route to the Pacific Ocean while also investigating the plant, animal, and other resources he encountered. The funds were raised, but Michaux eventually declined when the detailed interests of the two parties conflicted. That expedition would await the journey of Lewis and Clark under President Jefferson.
Edmond Genet, the newly arrived French ambassador to the Capital in Philadelphia, offered Michaux another opportunity of exploring westward. Here began Michaux's role as under cover agent. The vast expanse of the North American continent west of the Mississippi was still in the hands of the indigenous Tribes. European interests, largely French, British, and Spanish, had holdings, and designs, on this territory. The Spanish, for instance, held the city of New Orleans. This gave them control of shipping from the outlet of the Great River, something that irritated the American settlers who wished to use the port to ship their goods abroad without paying fees to a foreign nation.
The French, who were at war with Spain in Europe, wanted to have American settlers along the Ohio and Mississippi Rivers strike and dislodge the Spanish from New Orleans. Ambassador Genet engaged Michaux to head to Kentucky to help organize the locals to play this insurgent role. He would use his scientific investigations as cover for his visiting the area.
Author Spero reveals the role of many national and local government officials, including Secretary of State Jefferson, in abetting this plan. The United States had peaceful relations with Spain at this time, so participating in the French planned armed attack would violate American policy. The author notes that Jefferson's duplicitous behavior in this plot has been called traitorous by some earlier historians. He also uses the incident to identify the origin of political parties in the United States.
The subsequent varying fates of the many participants makes for interesting reading . Overall, an exciting journey through America's early history.
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